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  • 1. Cai, J
    et al.
    Guo, D.
    Khater, M
    Lavoie, C.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    SCHOTTKY FET FABRICATED WITH GATE LAST PROCESS2010Patent (Other (popular science, discussion, etc.))
  • 2. Cai, M.
    et al.
    Lavoie, C.
    Ozcan, A.
    Yang, B.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    SEMICONDUCTOR DEVICE WITH REDUCED JUNCTION LEAKAGE AND AN ASSOCIATED METHOD OF FORMING SUCH A SEMICONDUCTOR DEVICE2010Patent (Other (popular science, discussion, etc.))
  • 3.
    Cao, Qing
    et al.
    IBM Watson Research.
    Han, Shu-Jen
    IBM Watson Research.
    Tersoff, Jerry
    IBM Watson Research.
    Franklin, Aaron
    IBM Watson Research.
    Zhu, Yu
    IBM Watson Research.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. IBM Watson Research.
    Tulevski, George
    IBM Watson Research.
    Tang, Jianshi
    Haensch, Wilfried
    End-Bonded Mo2C Contacts for Carbon Nanotube Transistors with Low, Size-Independent Resistance2015In: Science, ISSN 0036-8075, E-ISSN 1095-9203Article in journal (Refereed)
  • 4. Chang, J.
    et al.
    Lavoie, C.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    SOURCE/DRAIN TECHNOLOGY FOR THE CARBON NANO-TUBE/GRAPHENE CMOS WITH A SINGLE SELF-ALIGNED METAL SILICIDE PROCESS2010Patent (Other (popular science, discussion, etc.))
  • 5.
    Chen, Si
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Luo, Chao
    University of Science and Technology of China.
    Zhang, Yujing
    University of Science and Technology of China.
    Xu, Jun
    University of Science and Technology of China.
    Hu, Qitao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Guo, Guoping
    University of Science and Technology of China.
    Current gain enhancement for silicon-on-insulator lateral bipolar junction transistors operating at liquid-helium temperature2020In: IEEE Electron Device Letters, ISSN 0741-3106, E-ISSN 1558-0563, Vol. 41, no 6, p. 800-803Article in journal (Refereed)
    Abstract [en]

    Conventional homojunction bipolar junction transistors (BJTs) are not suitable for cryogenic operation due to heavy doping-induced emitter band-gap narrowing and strong degradation in current gain (β) at low temperature. In this letter, we show that, on lateral version of the BJTs (LBJTs) fabricated on silicon-on-insulator (SOI) substrate, such β degradation can be mitigated by applying a substrate bias (V sub ), and a β over unity is achieved in a base current (I B ) range over 5 orders of magnitudes at 4.2 K, with a peak β ~ 100 demonstrated. The β improvement is explained by the enhanced electron tunneling through base region as a result of base barrier lowering and thinning by a positive Vsub, which leads to dramatic increase of collector current (IC) while IB is negligibly affected.

  • 6.
    Chen, Xi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Hu, Qitao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Solomon, Paul
    IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Device noise reduction for Silicon nanowire field-effect-transistor based sensors by using a Schottky junction gate2019In: ACS Sensors, E-ISSN 2379-3694, Vol. 4, no 2, p. 427-433Article in journal (Refereed)
    Abstract [en]

    The sensitivity of metal-oxide-semiconductor field-effect transistor (MOSFET) based nanoscale sensors is ultimately limited by noise induced by carrier trapping/detrapping processes at the gate oxide/semiconductor interfaces. We have designed a Schottky junction gated silicon nanowire field-effect transistor (SiNW-SJGFET) sensor, where the Schottky junction replaces the noisy oxide/semiconductor interface. Our sensor exhibits significantly reduced noise, 2.1×10-9 V2µm2/Hz at 1 Hz, compared to reference devices with the oxide/semiconductor interface operated at both inversion and depletion modes. Further improvement can be anticipated by wrapping the nanowire by such a Schottky junction thereby eliminating all oxide/semiconductor interfaces. Hence, a combination of the low-noise SiNW-SJGFET sensor device with a sensing surface of the Nernstian response limit holds promises for future high signal-to-noise ratio sensor applications.

  • 7.
    Chen, Xi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Solomon, Paul
    IBM Corp, Div Res, TJ Watson Res Ctr, Yorktown Hts, NY 10598 USA.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Top-bottom gate coupling effect on low frequency noise in a Schottky junction gated silicon nanowire field-effect transistor2019In: IEEE Journal of the Electron Devices Society, E-ISSN 2168-6734, Vol. 7, p. 696-700Article in journal (Refereed)
    Abstract [en]

    In this letter, strong low frequency noise (LFN) reduction is observed when the buried oxide (BOX)/silicon interface of a Schottky junction gated silicon nanowire field-effect transistor (SJGFET) is depleted by a substrate bias. Such LFN reduction is mainly attributed to the dramatic reduction in Coulomb scattering when carriers are pushed away from the interface. The BOX/silicon interface depletion can also be achieved by sidewall Schottky junction gates in a narrow channel SJGFET, leading to an optimal LFN performance without the need of any substrate bias.

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  • 8.
    Chen, Xi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Solomon, Paul
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. IBM Thomas J. Watson Research Center.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Low-Noise Schottky Junction Trigate Silicon Nanowire Field-effect Transistor for Charge Sensing2019In: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 66, no 9, p. 3994-4000Article in journal (Refereed)
    Abstract [en]

    Silicon nanowire (SiNW) field-effect transistors (SiNWFETs) are of great potential as a high-sensitivity charge sensor. The signal-to-noise ratio (SNR) of an SiNWFET sensor is ultimately limited by the intrinsic device noise generated by carrier trapping/detrapping processes at the gate oxide/silicon interface. This carrier trapping/detrapping-induced noise can be significantly reduced by replacing the noisy oxide/silicon interface with a Schottky junction gate (SJG) on the top of the SiNW. In this paper, we present a tri-SJG SiNWFET (Tri-SJGFET) with the SJG formed on both the top surface and the two sidewalls of the SiNW so as to enhance the gate control over the SiNW channel. Both experiment and simulation confirm that the additional sidewall gates in a narrow Tri-SJGFET indeed can confine the conduction path within the bulk of the SiNW channel away from the interfaces and significantly improve the immunity to the traps at the bottom buried oxide/silicon interface. Therefore, the optimal low-frequency noise performance can be achieved without the need for any substrate bias. This new gating structure holds promises for further development of robust SiNWFET-based charge sensors with low noise and low operation voltage.

  • 9.
    Chen, Xi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Hu, Qitao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Netzer, Nathan L.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Wang, Zhenqiang
    Univ South Dakota, Dept Chem, Churchill Haines Labs, Room 115,414 East Clark St, Vermillion, SD 57069 USA.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Multiplexed analysis of molecular and elemental ions using nanowire transistor sensors2018In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 270, p. 89-96Article in journal (Refereed)
    Abstract [en]

    An integrated sensor chip with silicon nanowire ion-sensitive field-effect transistors for simultaneous and selective detection of both molecular and elemental ions in a single sample solution is demonstrated. The sensing selectivity is realized by functionalizing the sensor surface with tailor-made mixed-matrix membranes (MMM) incorporated with specific ionophores for the target ions. A biomimetic container molecule, named metal-organic supercontainer (MOSC), is selected as the ionophore for detection of methylene blue (MB+), a molecular ion, while a commercially available Na-ionophore is used for Na+, an elemental ion. The sensors show a near-Nernstian response with 56.4 ± 1.8 mV/dec down to a concentration limit of ∌1 ΌM for MB+ and 57.9 ± 0.7 mV/dec down to ∌60 ΌM for Na+, both with excellent reproducibility. Extensive control experiments on the MB+ sensor lead to identification of the critical role of the MOSC molecules in achieving a stable and reproducible potentiometric response. Moreover, the MB+-specific sensor shows remarkable selectivity against common interfering elemental ions in physiological samples, e.g., H+, Na+, and K+. Although the Na+-specific sensor is currently characterized by insufficient immunity to the interference by MB+, the root cause is identified and remedies generally applicable for hydrophobic molecular ions are discussed. River water experiments are also conducted to prove the efficacy of our sensors.

  • 10.
    Chen, Xi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Tao
    NanoBeam Limited, Cambridge CB1 3HD, England, United Kingdom.
    Constantoudis, Vassilios
    NCSR Demokritos, Inst Nanosci & Nanotechnol, Attiki, Greece;Nanometrisis PC, Attiki, Greece.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Aged hydrogen silsesquioxane for sub-10 nm line patterns2016In: Microelectronic Engineering, ISSN 0167-9317, E-ISSN 1873-5568, Vol. 163, p. 105-109Article in journal (Refereed)
    Abstract [en]

    Hydrogen silsesquioxane (HSQ) has been used as a negative tone resist in electron beam lithography to define sub-10 nm patterns. The spontaneous polymerization in HSQ usually called aging in this context, sets a restricted period of time for a vendor-warranted use in patterning such small features with satisfactory line-edge roughness (LER). Here, we study the effect of HSQ aging on sensitivity and LER by focusing on exposing line patterns of 10 nm width in various structures. The results show that the 10 nm lines are easily achievable and the LER of the patterned lines remains unaltered even with HSQ that is stored 10 months beyond the vendor-specified expiration date. However, an increasingly pronounced decrease with time of the threshold electron dose (D-th), below which the line width would become less than 10 nm, is observed. After the HSQ expiration for 10 months, the 10 nm lines can be manufactured by reducing D-th to a level that is technically manageable with safe margins. In addition, the inclusion of a prebaldng step at 220 degrees C to accelerate the aging process results in a further reduced D-th for the 10 nm lines and thereby leads to a shortened writing time. The time variation of D-th with respect to the vendor-specified production date of HSQ is found to follow an exponential function of time and can be associated to the classical nucleation-growth polymerization process in HSQ.

  • 11.
    Cheng, K.
    et al.
    IBM research.
    Dennard, R.
    IBM Research.
    Zhang, Z.
    IBM Research.
    SEMICONDUCTOR DEVICE INCLUDING DUAL-LAYER SOURCE/DRAIN REGION2015Patent (Other (popular science, discussion, etc.))
  • 12. Cheng, K
    et al.
    Khakifirooz, A.
    Kulkarni, P.
    Ponoth, S.
    Kumar, A.
    Adam, T.
    Reznicek, A.
    Loubet, N.
    He, H.
    Kuss, J.
    Wang, M.
    Levin, T.
    Monsieur, F.
    Liu, Q.
    Sreenivasan, R.
    Cai, J.
    Kimball, A.
    Mehta, S.
    Luning, S.
    Zhu, Y.
    Zhu, Z.
    Yamaoto, T.
    Bryant, A.
    Lin, C.
    Naczas, S.
    Jagannathan, H.
    Edge, L.
    Allegret-Maret, S.
    Dube, A.
    Kanakasabapathy, S.
    Schmitz, S.
    Inada, A.
    Seo, S.
    Raymond, M.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Yagishita, A.
    Demarest, J.
    Li, J.
    Hopstaken, M.
    Berliner, N.
    Upham, A.
    Johnson, R.
    Holmes, S.
    Standaert, T.
    Smalley, M.
    Zamdmer, N.
    Ren, Z.
    Wu, T.
    Bu, H
    Paruchuri, V.
    Sadana, D.
    Narayanan, V.
    Haensch, W.
    O'Neill, J.
    Hook, T.
    Khare, M.
    Doris, B.
    ETSOI CMOS for System-on-Chip Applications Featuring 22nm Gate Length, Sub-100nm Gate Pitch, and 0.08mm2 RAM Cell2011Conference paper (Refereed)
  • 13. Fletcher, B.
    et al.
    Lavoie, C.
    Maurer, S.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    A METHOD TO ENABLE THE PROCESS AND ENLARGE THE PROCESS WINDOW FOR THE SILICIDAITION OF SUSPENDED SI STRUCTURES WITH EXTREMELY SMALL DIMENSION2011Patent (Other (popular science, discussion, etc.))
  • 14. Fritz, G.
    et al.
    Pyzyna, A.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Liu, F.
    Guillorn, M.
    Rodbell, K.
    Wisnieff, R.
    Interconnect Material Choices for Future Scaled Devices2012Conference paper (Refereed)
  • 15.
    Gao, Xindong
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Andersson, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Smith, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Lu, J.
    Hultman, L.
    Kellock, A.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Lavoie, C.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Epitaxy of Ultrathin NiSi2 Films with Predetermined Thickness2011In: Electrochemical and solid-state letters, ISSN 1099-0062, E-ISSN 1944-8775, Vol. 12, p. H268-H270Article in journal (Refereed)
  • 16. Guillorn, M.
    et al.
    Chang, J
    Pyzyna, A.
    Engelmann, S.
    Glodde, M.
    Joseph, E.
    Bruce, R.
    Ott, J.
    Majumdar, A.
    Liu, F.
    Brink, M.
    Bangsaruntip, S.
    Khater, M.
    Lauer, I
    Duch, E.
    Lavoie, C.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Newbury, J.
    Kratschmer, E.
    Klaus, D.
    Bucchignano, J.
    To, B.
    Graham, W.
    Sikorski, E.
    Narayanan, V.
    Fuller, N.
    Haensch, W.
    A 0.021 mm2 trigate SRAM cell with aggressively scaled gate and contact pitch2011Conference paper (Refereed)
  • 17. Guillorn, M.
    et al.
    Joseph, E
    Liu, F.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    SILICIDE MICROMECHANICAL DEVICE AND METHODS TO FABRICATE SAME2011Patent (Other (popular science, discussion, etc.))
  • 18.
    Hinnemo, Malkolm
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Makaraviciute, Asta
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Ahlberg, Patrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Olsson, Jörgen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhi-Bin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Protein sensing beyond the Debye Length Using Graphene Field-effect Transistors2018In: IEEE Sensors Journal, ISSN 1530-437X, E-ISSN 1558-1748, Vol. 18, no 16, p. 6497-6503Article in journal (Refereed)
    Abstract [en]

    Sensing biomolecules in electrolytes of high ionic strength has been a difficult challenge for field-effect transistor-based sensors. Here, we present a graphene-based transistor sensor that is capable of detection of antibodies against protein p53 in electrolytes of physiological ionic strength without dilution. As these molecules are much larger than the Debye screening length at physiological ionic strengths, this paper proves the concept of detection beyond the Debye length. The measured signal associated with the expected specific binding of the antibodies to p53 is concluded to result from resistance changes at the graphene-electrolyte interface, since a sensor responding to resistance changes rather than charge variations is not limited by Debye screening. The conclusion with changes in interface resistance as the underlying phenomena that lead to the observed signal is validated by impedance spectroscopy, which indeed shows an increase of the total impedance in proportion to the amounts of bound antibodies. This finding opens up a new route for electrical detection of large-size and even neutral biomolecules for biomedical detection applications with miniaturized sensors.

  • 19.
    Hu, Qitao
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Solomon, Paul
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Ion Sensing with Single Charge Resolution Using Sub-10 nm Electrical Double Layer Gated Silicon Nanowire TransistorsIn: Article in journal (Refereed)
  • 20.
    Hu, Qitao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Solomon, Paul
    IBM Corp, Thomas J Watson Res Ctr, POB 704, Yorktown Hts, NY 10598 USA..
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Ion sensing with single charge resolution using sub-10-nm electrical double layer-gated silicon nanowire transistors2021In: Science Advances, E-ISSN 2375-2548, Vol. 7, no 49, article id eabj6711Article in journal (Refereed)
    Abstract [en]

    Electrical sensors have been widely explored for the analysis of chemical/biological species. Ion detection with single charge resolution is the ultimate sensitivity goal of such sensors, which is yet to be experimentally demonstrated. Here, the events of capturing and emitting a single hydrogen ion (H+) at the solid/liquid interface are directly detected using sub-10-nm electrical double layer-gated silicon nanowire field-effect transistors (SiNWFETs). The SiNWFETs are fabricated using a complementary metal-oxide-semiconductor compatible process, with a surface reassembling step to minimize the device noise. An individually activated surface Si dangling bond (DB) acts as the single H+ receptor. Discrete current signals, generated by the single H+-DB interactions via local Coulomb scattering, are directly detected by the SiNWFETs. The single H+-DB interaction kinetics is systematically investigated. Our SiNWFETs demonstrate unprecedented capability for electrical sensing applications, especially for investigating the physics of solid/liquid interfacial interactions at the single charge level.

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    FULLTEXT01
  • 21.
    Hu, Qitao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Solomon, Paul
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Single Charge Detection in Liquid Sample Using Sub-10 nm Silicon Nanowire TransistorsIn: Article in journal (Other academic)
    Abstract [en]

    Direct detection of a single charge in liquid sample is the ultimate sensitivity goal of electrical biochemical sensors. In this paper, the events of capturing and emitting a single hydrogen ion (H+) at the solid/liquid interface were directly detected for the first time using sub-10 nm gate-oxide free silicon nanowire field-effect transistors (SiNWFETs). The SiNWFETs were fabricated using CMOS-compatible process. The intrinsic device noise was minimized with a surface reassembling process. Individually activated surface Si dangling bond (DB) acted as single H+ receptor. Discrete current signals generated by single H+-DB interactions via local Coulomb scattering were detected by the SiNWFETs. The kinetics of the single H+-DB interactions was systematically investigated. Our devices demonstrate the unprecedented ability to investigate the physics of solid/liquid interface at single charge level.

  • 22.
    Hu, Qitao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Wang, Zhenqiang
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Improving Selectivity of Ion-Sensitive Membrane by Polyethylene Glycol Doping2021In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 328, article id 128955Article in journal (Refereed)
    Abstract [en]

    Hydrophobic ions can generate considerable interference to ion detection in a complex analyte with membrane-based ion-selective sensors, due to the hydrophobic interaction. In this paper, we demonstrate that the interference from the hydrophobic interaction to the sensors can be significantly reduced by incorporating hydrophilic polyethylene glycol (PEG) into the membrane. The sensor is a silicon nanowire field-effect transistor (SiNWFET) with its surface functionalized with an ionophore-doped mixed-matrix membrane (MMM), where the ionophore is either a commercial Na-ionophore Ⅲ or a novel synthetic metal-organic supercontainer. The incorporation of PEG suppresses the partitioning of hydrophobic ions into the MMM and thus reduces their interference to the detection of target ions. This is evidenced with an improvement in selectivity for Na+ detection in the presence of interfering methylene blue (MB+) ion by more than an order of magnitude. It further enables detection of Na+ and MB+ using a SiNWFET sensor array in a multiplexed manner with controlled susceptivity to cross-interference and a greatly expanded dynamic range.

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    fulltext
  • 23.
    Hu, Qitao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Solomon, Paul
    IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Effects of Substrate Bias on Low-Frequency Noise in Lateral Bipolar Transistors Fabricated on Silicon-on-Insulator Substrate2020In: IEEE Electron Device Letters, ISSN 0741-3106, E-ISSN 1558-0563, Vol. 41, no 1, p. 4-7Article in journal (Refereed)
    Abstract [en]

    This letter presents a systematic study of how the substrate bias (Vsub) modulation affects the current-voltage (I-V) characteristics and low-frequency noise (LFN) of lateral bipolar junction transistors (LBJTs) fabricated on a silicon-on-insulator(SOI) substrate. The current gain (β) of npn LBJTs at low base voltage can be greatly improved bya positive Vsub as a result of enhanced electron injection into the base near the buried oxide (BOX)/silicon interface. However, an excessive positive Vsub may also adversely affect the LFN performance by amplifying the noise generated as a result of carrier trapping and detrapping at that interface. Our results provide a practical guideline for improving both β and the overall noise performance when using our LBJT as a local signal amplifier.

  • 24.
    Hu, Qitao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Xi
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Norström, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zeng, Shuangshuang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Liu, Yifei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Fredrik, Gustavsson
    Swerea KIMAB, Stockholm, Sweden.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Current gain and low-frequency noise of symmetric lateral bipolar junction transistors on SOI2018In: 2018 48th European Solid-State Device Research Conference (ESSDERC), 2018, p. 258-261Conference paper (Refereed)
    Abstract [en]

    This paper presents a comprehensive study of symmetric lateral bipolar junction transistors (LBJTs) fabricated on SOI substrate using a CMOS-compatible process; LBJTs find many applications including being a local signal amplifier for silicon-nanowire sensors. Our LBJTs are characterized by a peak gain (β) over 50 and low-frequency noise two orders of magnitude lower than what typically is of the SiO 2 /Si interface for a MOSFET. β is found to decrease at low base current due to recombination in the space charge region at the emitter-base junction and at the surrounding SiO 2 /Si interfaces. This decrease can be mitigated by properly biasing the substrate.

  • 25.
    Hu, Qitao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Solomon, Paul
    IBM T. J. Watson Research Center.
    Österlund, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Solid State Physics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Nanotransistor-based gas sensing with record-high sensitivity enabled by electron trapping effect in nanoparticles2024In: Nature Communications, E-ISSN 2041-1723, Vol. 15, no 1, article id 5259Article in journal (Refereed)
    Abstract [en]

    Highly sensitive, low-power, and chip-scale H2 gas sensors are of great interest to both academia and industry. Field-effect transistors (FETs) functionalized with Pd nanoparticles (PdNPs) have recently emerged as promising candidates for such H2 sensors. However, their sensitivity is limited by weak capacitive coupling between PdNPs and the FET channel. Herein we report a nanoscale FET gas sensor, where electrons can tunnel between the channel and PdNPs and thus equilibrate them. Gas reaction with PdNPs perturbs the equilibrium, and therefore triggers electron transfer between the channel and PdNPs via trapping or de-trapping with the PdNPs to form a new balance. This direct communication between the gas reaction and the channel enables the most efficient signal transduction. Record-high responses to 1–1000 ppm H2 at room temperature with detection limit in the low ppb regime and ultra-low power consumption of ∼300 nW are demonstrated. The same mechanism could potentially be used for ultrasensitive detection of other gases. Our results present a supersensitive FET gas sensor based on electron trapping effect in nanoparticles.

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  • 26.
    Hu, Qitao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chen, Si
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Symmetric Lateral Bipolar Transistors as Low Noise Signal Amplifier2019Conference paper (Other academic)
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  • 27.
    Hu, Qitao
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    FET gas sensor device2022Patent (Other (popular science, discussion, etc.))
  • 28.
    Jablonka, Lukas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Abedin, Ahmad
    Department of Electronics, KTH Royal Institute of Technology, SE-16440 Stockholm, Sweden.
    Hellström, Per-Erik
    Department of Electronics, KTH Royal Institute of Technology, SE-16440 Stockholm, Sweden.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    A novel route to a reliable extraction of the specific contact resistivity of the germanium/nickel germanide interfaceManuscript (preprint) (Other academic)
  • 29.
    Jablonka, Lukas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kubart, Thomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Gustavsson, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Abedin, Ahmad
    KTH Royal Institute of Technology.
    Hellström, Per-Erik
    KTH Royal Institute of Technology.
    Östling, Mikael
    KTH Royal Institute of Technology.
    Jordan-Sweet, Jean L.
    IBM, TJ Watson Research Center.
    Lavoie, Christian
    IBM, TJ Watson Research Center.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Scalability Study of Nickel Germanides2016Conference paper (Refereed)
  • 30.
    Jablonka, Lukas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Gustavsson, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Swerea KIMAB AB, Box 7047, SE-16407 Kista, Sweden.
    Descoins, Marion
    Univ Aix Marseille, CNRS, IM2NP, Case 142, F-13397 Marseille 20, France.
    Mangelinck, Dominique
    Univ Aix Marseille, CNRS, IM2NP, Case 142, F-13397 Marseille 20, France.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Improving the morphological stability of nickel germanide by tantalum and tungsten additions2018In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 112, no 10, article id 103102Article in journal (Refereed)
    Abstract [en]

    To enhance the morphological stability of NiGe, a material of interest as a source drain-contact in Ge-based field effect transistors, Ta or W, is added as either an interlayer or a capping layer. The efficacy of this Ta or W addition is evaluated with pure NiGe as a reference. While interlayers increase the NiGe formation temperature, capping layers do not retard the NiGe formation. Regardless of the initial position of Ta or W, the morphological stability of NiGe against agglomeration can be improved by up to 100 °C. The improved thermal stability can be ascribed to an inhibited surface diffusion, owing to Ta or W being located on top of NiGe after annealing, as confirmed by means of transmission electron microscopy, Rutherford backscattering spectrometry, and atom probe tomography. The latter also shows a 0.3 €‰at. % solubility of Ta in NiGe at 450 °C, while no such incorporation of W is detectable.

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  • 31.
    Jablonka, Lukas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Primetzhofer, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Abedin, Ahmad
    KTH Royal Inst Technol, Sch Informat & Commun Technol, SE-16440 Kista, Sweden..
    Hellstrom, Per-Erik
    KTH Royal Inst Technol, Sch Informat & Commun Technol, SE-16440 Kista, Sweden..
    Ostling, Mikael
    KTH Royal Inst Technol, Sch Informat & Commun Technol, SE-16440 Kista, Sweden..
    Jordan-Sweet, Jean
    IBM Corp, TJ Watson Res Ctr, Yorktown Hts, NY 10598 USA..
    Lavoie, Christian
    IBM Corp, TJ Watson Res Ctr, Yorktown Hts, NY 10598 USA..
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Formation of nickel germanides from Ni layers with thickness below 10 nm2017In: Journal of Vacuum Science & Technology B, ISSN 1071-1023, E-ISSN 1520-8567, Vol. 35, no 2, article id 020602Article in journal (Refereed)
    Abstract [en]

    The authors have studied the reaction between a Ge (100) substrate and thin layers of Ni ranging from 2 to 10 nm in thickness. The formation of metal-rich Ni5Ge3 was found to precede that of the monogermanide NiGe by means of real-time in situ x-ray diffraction during ramp-annealing and ex situ x-ray pole figure analyses for phase identification. The observed sequential growth of Ni5Ge3 and NiGe with such thin Ni layers is different from the previously reported simultaneous growth with thicker Ni layers. The phase transformation from Ni5Ge3 to NiGe was found to be nucleationcontrolled for Ni thicknesses < 5 nm, which is well supported by thermodynamic considerations. Specifically, the temperature for the NiGe formation increased with decreasing Ni (rather Ni5Ge3) thickness below 5 nm. In combination with sheet resistance measurement and microscopic surface inspection of samples annealed with a standard rapid thermal processing, the temperature range for achieving morphologically stable NiGe layers was identified for this standard annealing process. As expected, it was found to be strongly dependent on the initial Ni thickness.

  • 32.
    Jablonka, Lukas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Moskovkin, Pavel
    Laboratoire d'Analyse par Réactions Nucléaires (LARN), Namur Institute of Structured Matter (NISM), University of Namur (UNamur), Namur, Belgium.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Lucas, Stéphane
    Laboratoire d'Analyse par Réactions Nucléaires (LARN), Namur Institute of Structured Matter (NISM), University of Namur (UNamur), Namur, Belgium.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Metal Filling by High Power Impulse Magnetron Sputtering2019In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 52, no 36, article id 365202Article in journal (Refereed)
    Abstract [en]

    High power impulse magnetron sputtering (HiPIMS) is an emerging thin film deposition technology that provides a highly ionized flux of sputtered species. This makes HiPIMS attractive for metal filling of nanosized holes for highly scaled semiconductor devices. In this work, HiPIMS filling with Cu and Co is investigated. We show that the quality of the hole filling is determined mainly by the fraction of ions in the deposited flux and their energy. The discharge waveforms alone are insufficient to determine the ionization of the metal flux. The experimental results are in a good agreement with Monte-Carlo simulations using the measured flux characteristics. Based on the simulations, strategies to improve the filling are discussed.

  • 33.
    Jablonka, Lukas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Riekehr, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Highly conductive ultrathin Co films by high-power impulse magnetron sputtering2018In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 112, no 4, article id 043103Article in journal (Refereed)
    Abstract [en]

    Ultrathin Co films deposited on SiO2 with conductivities exceeding that of Cu are demonstrated. Ionized deposition implemented by high-power impulse magnetron sputtering (HiPIMS) is shown to result in smooth films with large grains and low resistivities, namely, 14 mu Omega cm at a thickness of 40 nm, which is close to the bulk value of Co. Even at a thickness of only 6 nm, a resistivity of 35 mu Omega cm is obtained. The improved film quality is attributed to a higher nucleation density in the Co-ion dominated plasma in HiPIMS. In particular, the pulsed nature of the Co flux as well as shallow ion implantation of Co into SiO2 can increase the nucleation density. Adatom diffusion is further enhanced in the ionized process, resulting in a dense microstructure. These results are in contrast to Co deposited by conventional direct current magnetron sputtering where the conductivity is reduced due to smaller grains, voids, rougher interfaces, and Ar incorporation. The resistivity of the HiPIMS films is shown to be in accordance with models by Mayadas-Shatzkes and Sondheimer which consider grain-boundary and surface-scattering.

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  • 34. Kellock, A.
    et al.
    Lavoie, C.
    Ozcan, A.
    Rossnagel, S.
    Yang, B.
    Zhu, Y.
    Zollner, S.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    SILICIDE CONTACT FORMATION2010Patent (Other (popular science, discussion, etc.))
  • 35. Khater, M.
    et al.
    Lavoie, C.
    Yang, B.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    METHOD FOR FORMING AN SOI SCHOTTKY SOURCE/DRAIN DEVICE TO CONTROL ENCROACHMENT AND DELAMINATION OF SILICIDE2010Patent (Other (popular science, discussion, etc.))
  • 36. Khater, M
    et al.
    Lavoie, C.
    Yang, B.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    SOI SCHOTTKY SOURCE/DRAIN DEVICE STRUCTURE TO CONTROL ENCROACHMENT AND DELAMINATION OF SILICIDE2010Patent (Other (popular science, discussion, etc.))
  • 37. Khater, M.
    et al.
    Lavoie, C.
    Yang, B.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    USE EPITAXIAL NI SILICIDE2010Patent (Other (popular science, discussion, etc.))
  • 38. Khater, M.
    et al.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Cai, J.
    Lavoie, C.
    D'emic, C.
    Yang, B.
    Yang, Q.
    Guillorn, M.
    Klaus, D.
    Ott, J.
    Zhu, Y.
    Choi, C.
    Frank, M.
    Lee, K.
    Narayanan, V.
    Park, D.
    Ouyang, C.
    Haensch, W.
    High-κ/Metal-Gate Fully Depleted SOI CMOS With Single-Silicide Schottky Source/Drain With Sub-30-nm Gate Length2010In: IEEE Electron Device Letters, ISSN 0741-3106, E-ISSN 1558-0563, Vol. 31, p. 275-277Article in journal (Refereed)
  • 39.
    Kubart, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Jablonka, Lukas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Metallization of nanostructures by High Power Impulse Magnetron Sputtering2015In: 4 th Magnetron, Ion processing & Arc Technologies European Conference, Paris, 8-11 December 2015, 2015Conference paper (Other academic)
    Abstract [en]

    In this contribution, we present the use of High Power Impulse Magnetron Sputtering (HiPIMS) for metallization of nanostructures for microelectronics. This work is motivated by meeting the increasing demands on deposition processes due to the increasing density of integration. Shrinking lateral dimensions of the structures more rapidly than vertical dimensions means increasing aspect ratios. There is also a need for deposition of new materials. Traditionally, ionized PVD (I-PVD) has been used for metallization of nanostructures. Unlike most other I-PVD techniques, HiPIMS is compatible with standard magnetron sputtering systems. It may therefore be an attractive alternative to the techniques with additional ionization of the sputtered metal flux. With two examples, we will show the great flexibility of HiPIMS in making conformal deposition vs. directed via filling.

    First, we show conformal formation of ultrathin Ni films in a modified self-aligned silicide process, thanks to the Ni ionization in HiPIMS. After appropriate annealing, the thickness of the resulting Ni-silicide films could be readily adjusted in the range from 4.7 to 8.6 nm by proper substrate biasing [1]. Good sidewall coverage was also achieved [2].

    Second, we discuss filling of via holes for vertical stacking at device level. Here, narrow (sub 100 nm) trenches and holes need to be filled with a highly conductive metal. We explore the potential of HiPIMS and determine the maximum aspect ratio that can be filled. In our experiment with Cu, the ionized metal flux fraction is estimated to be about 70% from the substrate from the substrate ion current. A significant improvement over DC sputtering has been achieved, as shown in Fig. 1, with success in filling vias of aspect ratio 1.5. We analyze the influence of ion energy and discuss approaches to further improving the filling process.

  • 40. Lavoie, C.
    et al.
    Ning, T.
    Ozcan, A.
    Yang, B.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    METAL-SEMICONDUCTOR INTERMIXED REGIONS2011Patent (Other (popular science, discussion, etc.))
  • 41. Lavoie, C.
    et al.
    Ozcan, A.
    Yang, B.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    METHOD TO CONTROL METAL SEMICONDUCTOR MICRO-STRUCTURE2010Patent (Other (popular science, discussion, etc.))
  • 42.
    Li, Chen
    et al.
    Fudan Univ, State Key Lab ASIC & Syst, Shanghai 200433, Peoples R China..
    Wen, Chenyu
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Zeng, Ruixue
    Fudan Univ, State Key Lab ASIC & Syst, Shanghai 200433, Peoples R China..
    Zeng, Shuangshuang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Qiu, Zhi-Jun
    Fudan Univ, State Key Lab ASIC & Syst, Shanghai 200433, Peoples R China..
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Wu, Dongping
    Fudan Univ, State Key Lab ASIC & Syst, Shanghai 200433, Peoples R China..
    Rapid Four-Point Sweeping Method to Investigate Hysteresis of MoS2 FET2020In: IEEE Electron Device Letters, ISSN 0741-3106, E-ISSN 1558-0563, Vol. 41, no 9, p. 1356-1359Article in journal (Refereed)
    Abstract [en]

    Hysteresis is a frequently observed phenomenon in the transfer characteristics of thin film transistors. Charge trapping/de-trapping processes of gate oxide and gate-channel interface are commonly known to be the origin of hysteresis and correlated to low frequency noise (LFN) properties of the devices. In this letter, a rapid four-point sweeping method (RFSM) is proposed to reveal the dependence of hysteresis, as well as the distribution of effective trap density on sweeping rate and gate bias range. Based on the RFSM, the hysteresis properties of four-layer MoS2 FETs are studied in detail. The experimental results demonstrate that the hysteresis and trap density at different frequencies and gate voltages, which could further roughly map the traps with different time constants and energy depths, can be obtained by the simple RFSM. Trap density estimated by RFSM shows a comparable range with that extracted from LFN, indicating that the traps inducing the hysteresis may also cause LFN.

  • 43.
    Li, Shiyu
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Zeng, Shuangshuang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Chen, Lei
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Nanoarrays on Passivated Aluminum Surface for Site-Specific Immobilization of Biomolecules2018In: ACS Applied Bio Materials, E-ISSN 2576-6422, Vol. 1, no 1, p. 125-135Article in journal (Refereed)
    Abstract [en]

    The rapid development of biosensing platforms for highly sensitive and specific detection raises the desire of precise localization of biomolecules onto various material surfaces. Aluminum has been strategically employed in the biosensor system due to its compatibility with CMOS technology and its optical and electrical properties such as prominent propagation of surface plasmons. Herein, we present an adaptable method for preparation of carbon nanoarrays on aluminum surface passivated with poly(vinylphosphonic acid) (PVPA). The carbon nanoarrays were defined by means of electron beam induced deposition (EBID) and they were employed to realize site-specific immobilization of target biomolecules. To demonstrate the concept, selective streptavidin/neutravidin immobilization on the carbon nanoarrays was achieved through protein physisorption with a significantly high contrast of the carbon domains over the surrounding PVPA-modified aluminum surface. By adjusting the fabrication parameters, local protein densities could be varied on similarly sized nanodomains in a parallel process. Moreover, localization of single 40 nm biotinylated beads was achieved by loading them on the neutravidin-decorated nanoarrays. As a further demonstration, DNA polymerase with a streptavidin tag was bound to the biotin-beads that were immobilized on the nanoarrays and in situ rolling circle amplification (RCA) was subsequently performed. The observation of organized DNA arrays synthesized by RCA verified the nanoscale localization of the enzyme with retained biological activity. Hence, the presented approach could provide a flexible and universal avenue to precise localizing various biomolecules on aluminum surface for potential biosensor and bioelectronic applications. 

  • 44.
    Li, Shiyu
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics. Uppsala University.
    Zeng, Shuangshuang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Wen, Chenyu
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Barbe, Laurent
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Microsystems Technology.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Microsystems Technology.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Microsystems Technology.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Dynamics of DNA Clogging in Hafnium Oxide Nanopores2020In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 124, no 51, p. 11573-11583Article in journal (Refereed)
    Abstract [en]

    Interfacing solid-state nanopores with biological systems has been exploited as a versatile analytical platform for analysis of individual biomolecules. Although clogging of solid-state nanopores due to nonspecific interactions between analytes and pore walls poses a persistent challenge in attaining the anticipated sensing efficacy, insufficient studies focus on elucidating the clogging dynamics. Herein, we investigate the DNA clogging behavior by passing double-stranded (ds) DNA molecules of different lengths through hafnium oxide(HfO2)-coated silicon (Si) nanopore arrays, at different bias voltages and electrolyte pH values. Employing stable and photoluminescent-free HfO2/Si nanopore arrays permits a parallelized visualization of DNA clogging with confocal fluorescence microscopy. We find that the probability of pore clogging increases with both DNA length and bias voltage. Two types of clogging are discerned: persistent and temporary. In the time-resolved analysis, temporary clogging events exhibit a shorter lifetime at higher bias voltage. Furthermore, we show that the surface charge density has a prominent effect on the clogging probability because of electrostatic attraction between the dsDNA and the HfO2 pore walls. An analytical model based on examining the energy landscape along the DNA translocation trajectory is developed to qualitatively evaluate the DNA–pore interaction. Both experimental and theoretical results indicate that the occurrence of clogging is strongly dependent on the configuration of translocating DNA molecules and the electrostatic interaction between DNA and charged pore surface. These findings provide a detailed account of the DNA clogging phenomenon and are of practical interest for DNA sensing based on solid-state nanopores.

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  • 45.
    Li, Shiyu
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Zeng, Shuangshuang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Wen, Chenyu
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Microsystems Technology.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Docking and Activity of DNA Polymerase on Solid-State Nanopores2022In: ACS Sensors, E-ISSN 2379-3694, Vol. 7, no 5, p. 1476-1483Article in journal (Refereed)
    Abstract [en]

    Integration of motor enzymes with biological nanopores has enabled commercial DNA sequencing technology; yet studies of the similar principle applying to solid-state nanopores are limited. Here, we demonstrate the real-life monitoring of phi29 DNA polymerase (DNAP) docking onto truncated-pyramidal nanopore (TPP) arrays through both electrical and optical readout. To achieve effective docking, atomic layer deposition of hafnium oxide is employed to reduce the narrowest pore opening size of original silicon (Si) TPPs to sub-10 nm. On a single TPP with pore opening size comparable to DNAP, ionic current measurements show that a polymerase-DNA complex can temporally dock onto the TPP with a certain docking orientation, while the majority become translocation events. On 5-by-5 TPP arrays, a label-free optical detection method using Ca2+ sensitive dye, are employed to detect the docking dynamics of DNAP. The results show that this label-free detection strategy is capable of accessing the docking events of DNAP on TPP arrays. Finally, we examine the activity of docked DNAP by performing on-site rolling circle amplification to synthesize single-stranded DNA (ssDNA), which serves as a proof-of-concept demonstration of utilizing this docking scheme for emerging nanopore sensing applications.

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  • 46.
    Li, Shiyu
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Zeng, Shuangshuang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Wen, Chenyu
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Microsystems Technology.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Label-Free Optical Detection of DNA Polymerase Docking on Solid-State Nanopore ArraysManuscript (preprint) (Other academic)
    Abstract [en]

    Integration of motor enzymes with biological nanopores has enabled commercial DNA sequencing, yet studies of the similar principle applying to solid-state nanopores are limited. Here, we demonstrate the label-free optical detection of phi29 DNA polymerase (DNAP) docking onto truncated-pyramidal nanopores (TPP). Atomic layer deposition of hafnium oxide is employed to shrink the pore opening size of original silicon (Si) TPP to sub-10 nm. Ionic current measurements of single TPP of an opening size comparable to DNAP show that polymerase-DNA complexes can temporally dock onto the TPP with a certain docking orientation, while the majority are translocation events. A label-free optical detection method using Ca2+ sensitive dye is employed to detect the docking of DNAP on 5-by-5 nanopore arrays. The results of the proof-of-concept experiment show that this label-free detection strategy is capable of accessing the docking events of DNAP on solid-state nanopore arrays.

  • 47.
    Li, Shiyu
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Zeng, Shuangshuang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Microsystems Technology.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Nanoparticle Localization on Solid-State Nanopores Via Electrophoretic Force2019In: 2019 20TH INTERNATIONAL CONFERENCE ON SOLID-STATE SENSORS, ACTUATORS AND MICROSYSTEMS & EUROSENSORS XXXIII (TRANSDUCERS & EUROSENSORS XXXIII), IEEE, 2019, p. 2372-2375Conference paper (Refereed)
    Abstract [en]

    This work presents a versatile and facile method for precise localization of nanoparticles on solid-state nanopores surface-functionalized with carbon via electron beam induced deposition (EBID). For the first time, EBID of carbon is demonstrated to enable nanoparticle localization on solid-state nanopores. To avoid non-specific adsorption of nanoparticles on the surface, an atomic layer deposited Al2O3 layer in combination with phosphonate passivation is used. By tuning the electron dose in the EBID process, the loading fraction of nanoparticles on carbon nanoarrays can be varied on similarly sized domains. Nanoparticle loading driven by electrophoresis can achieve an efficiency that is orders of magnitude higher than that driven by diffusion.

  • 48.
    Li, Shiyu
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Zeng, ShuangshuangUppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.Zhang, ZhenUppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.Hjort, KlasUppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.Zhang, Shi-LiUppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Optical monitoring of single nanoparticle capture in solid-state nanopore array2019Conference proceedings (editor) (Refereed)
    Abstract [en]

    Solid-state nanopore arrays hold promises for high-throughput optical or electrical analysis of nanoscale entities. Here, we demonstrate an optical monitoring system for investigation of the capture process of single nanoparticles driven by electrophoretic force in a nanopore array. Over 50% of the single nanoparticle capture events are achieved by controlling the applied voltage across the nanopore membrane with a tailored nanopore size. We find that at a certain voltage bias, the capture of single nanoparticles is a self-termination process.

  • 49.
    Li, Shiyu
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics. Uppsala University.
    Zeng, ShuangshuangUppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.Zhang, ZhenUppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.Hjort, KlasUppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.Zhang, Shi-LiUppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Parallelized single-molecule translocations in arrayed silicon nanopores coated with a lipid bilayer2019Conference proceedings (editor) (Refereed)
    Abstract [en]

    Solid-state nanopores have been recognized as a versatile tool for single-molecule detection with high sensitivity. They have been extensively studied for analysis by nanopore translocation of biomolecules, such as DNA, RNA, and proteins. As a complement to the electrical sensing readout, optical sensing of labeled molecules on a solid-state nanopore array can notably enhance the sensing capacity with high throughput. However, the widely used silicon nitride (SiNx) nanopore produces significant photoluminescence (PL) background under blue-green laser illumination, which can severely limit, e.g., multicolor sensing for DNA barcode discrimination. In addition, the occasionally occurring irreversible DNA clogging in a solid-state nanopore, because of DNA molecules interacting with the nanopore channel wall during translocation, can seriously affect the sensing efficacy and accuracy. To address these problems, we have developed an optical sensing system dedicated to nanopore arrays fabricated in a free-standing silicon membrane with its surface functionalized by lipid bilayer coating.

    A silicon nanopore array with pores of sub-20 nm diameter is fabricated in a silicon-on-insulator wafer using electron beam lithography in combination with anisotropic etching. The 55 nm thick free-standing silicon membrane shows negligible PL emission in the 550 to 800 nm spectral range under blue-green laser illumination, which greatly improves the optical signal-to-background ratio for single-molecule detection in comparison with standard SiNx devices. The formation of a lipid bilayer on the nanopore walls is successful as inferred by monitoring in situ the stepwise reduction of the nanopore conductance of ionic current and subsequently by observing ex situ the homogenous fluorescence emitted from a labeled lipid bilayer. As a demonstration, we perform the optical sensing measurements with a conventional wide-field microscope to detect the translocation of fluorophore-labeled DNA strands (120 kbp). With the low background PL of the silicon membrane, the optical signal of individual DNA translocation events is more clearly identified than when using similarly processed SiNx nanopore devices. Moreover, the coated fluidic lipid bilayer provides a nonstick surface to minimize the non-specific interaction of DNA molecules with the silicon pore walls. The results show that the DNA clogging is substantially reduced in the lipid bilayer coated nanopores as compared to uncoated nanopores. These results demonstrate that using silicon nanopores coated by a lipid bilayer is a promising strategy to realizing massively-parallel single-molecule optical detection.

  • 50.
    Li, Shiyu
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Zeng, Shuangshuang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science and Engineering, Microsystems Technology.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Solid-State Electronics.
    Visualization of DNA Translocation and Clogging Using Photoluminescent-Free Silicon Nanopore Arrays2020In: 2020 IEEE 20th International Conference on Nanotechnology (IEEE-NANO), Institute of Electrical and Electronics Engineers (IEEE) , 2020, p. 193-197Conference paper (Refereed)
    Abstract [en]

    Solid-state nanopore arrays hold promises for high-throughput optical analysis of single molecules. However, the high photoluminescence (PL) background emanating from the commonly used silicon nitride (SiNx) membrane for nanopore fabrication and the nonspecific adsorption of analyte on the pore sidewalls have plagued the high sensing sensitivity and efficiency offered by optical sensing. Here, the present work demonstrates an optical monitoring system using a truncated pyramidal nanopore array on a silicon membrane coated with a lipid bilayer for visualization of DNA translocation events. The silicon membrane produces essentially no PL under blue-green laser illumination, which enables more clear identification of DNA translocation and clogging events than using SiNx-based devices. The lipid bilayer coating based on small unilamellar vesicles (SUVs) minimizes the nonspecific adsorption of DNA. With confocal microscopy, the fluorescent labeled DNA translocation motion is visualized in three dimensions. The statistical results show that the percentage of DNA clogged pores is significantly reduced for the lipid bilayer coated nanopores as compared to the uncoated nanopores.

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