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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, 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.

  • 6.
    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.

  • 7.
    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.))
  • 8. 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)
  • 9. 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.))
  • 10. 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)
  • 11.
    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)
  • 12. 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)
  • 13. 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.))
  • 14.
    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)
  • 15.
    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.
    Descoins, Marion
    Mangelinck, Dominique
    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 10Article 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.

  • 16.
    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.

  • 17.
    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.

  • 18. 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.))
  • 19. 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.))
  • 20. 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.))
  • 21. 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.))
  • 22. 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)
  • 23.
    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.

  • 24. 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.))
  • 25. 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.))
  • 26. Liu, F.
    et al.
    Fletcher, B.
    Joseph, E.
    Zhu, Y.
    Gonsalves, J.
    Price, W.
    Fritz, G.
    Engelmann, S.
    Pyzyna, A.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Cabral, C.
    Guillorn, M.
    Subtractive W Contact and Local Interconnect Co-integration (CLIC)2013Conference paper (Refereed)
  • 27. Luo, J.
    et al.
    Qiu, Z.
    Zha, C.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Wu, D.
    Lu, J.
    Akerman, J.
    Ostling, M.
    Hultman, L.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Surface-energy triggered phase formation and epitaxy in nanometer-thick Ni1−xPtx silicide films2010In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 96, p. 071915-Article in journal (Refereed)
  • 28. Luo, J
    et al.
    Qiu, Z.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Ostling, M.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Interaction of NiSi with dopants for metallic source/drain applications2010In: Journal of Vacuum Science & Technology B, ISSN 1071-1023, E-ISSN 1520-8567, Vol. 28, p. 1071-Article in journal (Refereed)
  • 29.
    Luo, Jun
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Qiu, Zhi-Jun
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Östling, Mikael
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Interaction of NiSi with dopants for metallic source/drain applications2010In: Journal of Vacuum Science & Technology B, ISSN 1071-1023, E-ISSN 1520-8567, Vol. 28, no 1, p. C1I1-C1I11Article in journal (Refereed)
    Abstract [en]

    This work has a focus on NiSi as a possible metallic contact for aggressively scaled complementary metal oxide semiconductor devices. As the bulk work function of NiSi lies close to the middle of Si bandgap, the Schottky barrier height (SBH) of NiSi is rather large for both electron ( ∼ 0.65 eV) and hole ( ∼ 0.45 eV). Different approaches have therefore been intensively investigated in the literature aiming at reducing the effective SBH: dopant segregation (DS), surface passivation (SP), and alloying, in order to improve the carrier injection into the conduction channel of a field-effect transistor. The present work explores DS using B and As for the NiSi/Si contact system. The effects of C and N implantation into Si substrate prior to the NiSi formation are examined, and it is found that the presence of C yields positive effects in helping reduce the effective SBH to 0.1–0.2 eV for both conduction polarities. A combined use of DS or SP with alloying could be considered for more effective control of effective SBH, but an examination of undesired compound formation and its probable consequences is necessary. Furthermore, an analysis of the metal silicides that have a small “intrinsic” SBH reveals that only a very small number of them are of practical interest as most of the silicides require either a high formation temperature or possess a high specific resistivity.

  • 30. Luo, Jun
    et al.
    Zhijun, Qiu
    Chaolin, Zha
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Dongping, Wu
    Jun, Lu
    Johan, Akerman
    Mikael, Ostling
    Lars, Hultman
    Shi-Li, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Surface-energy triggered phase formation and epitaxy in nanometer-thick Ni1−xPtx silicide films2010In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 96, no 3, p. 031911-Article in journal (Refereed)
    Abstract [en]

    The formation of ultrathin silicide films of Ni1−xPtx at 450–850 °C is reported. Without Pt (x=0) and for tNi<4 nm, epitaxially aligned NiSi2−y films readily grow and exhibit extraordinary morphological stability up to 800 °C. For tNi≥4 nm, polycrystalline NiSi films form and agglomerate at lower temperatures for thinner films. Without Ni (x=1) and for tPt=1–20 nm, the annealing behavior of the resulting PtSi films follows that for the NiSi films. The results for Ni1−xPtx of other compositions support the above observations. Surface energy is discussed as the cause responsible for the distinct behavior in phase formation and morphological stability.

  • 31.
    Makaraviciute, Asta
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Xu, Xingxing
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Nyholm, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Systematic approach to the development of microfabricated biosensors: relationship between the gold surface pretreatment and thiolated molecule binding2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 31, p. 26610-26621Article in journal (Refereed)
    Abstract [en]

    Despite the increasing popularity of microfabricated biosensors due to advances in technologic and surface functionalization strategies, their successful implementation is partially inhibited by the lack of consistency in their analytical characteristics. One of the main causes for the discrepancies is the absence of a systematic and comprehensive approach to surface functionalization. In this article microfabricated gold electrodes aimed at biosensor development have been systematically characterized in terms of surface pretreatment, thiolated molecule binding, and reproducibility by means of X-ray photoelectron scattering (XPS) and cyclic voltammetry (CV). It has been shown that after SU-8 photolithography gold surfaces were markedly contaminated, which decreased the effective surface area and surface coverage of a model molecule mercaptohexanol (MCH). Three surface pretreatment methods compatible with microfabricated devices were compared. The investigated methods were (i) cyclic voltammetry in dilute H2SO4, (ii) gentle basic piranha followed by linear sweep voltammetry in dilute KOH, and (iii) oxygen plasma treatment followed by incubation in ethanol. It was shown that all three methods significantly decreased the contamination and increased MCH surface coverage. Most importantly, it was also revealed that surface pretreatments may induce structural changes to the gold surfaces. Accordingly, these alterations influence the characteristics of MCH functionalization.

  • 32.
    Netzer, Nathan L.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Must, Indrek
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Qiao, Yupu
    Univ South Dakota, Dept Chem, 414 E 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.
    Wang, Zhenqiang
    Univ South Dakota, Dept Chem, 414 E Clark St, Vermillion, SD 57069 USA..
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Biomimetic supercontainers for size-selective electrochemical sensing of molecular ions2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 45786Article in journal (Refereed)
    Abstract [en]

    New ionophores are essential for advancing the art of selective ion sensing. Metal-organic supercontainers (MOSCs), a new family of biomimetic coordination capsules designed using sulfonylcalix[4] arenes as container precursors, are known for their tunable molecular recognition capabilities towards an array of guests. Herein, we demonstrate the use of MOSCs as a new class of size-selective ionophores dedicated to electrochemical sensing of molecular ions. Specifically, a MOSC molecule with its cavities matching the size of methylene blue (MB+), a versatile organic molecule used for bio-recognition, was incorporated into a polymeric mixed-matrix membrane and used as an ion-selective electrode. This MOSC-incorporated electrode showed a near-Nernstian potentiometric response to MB+ in the nano-to micro-molar range. The exceptional size-selectivity was also evident through contrast studies. To demonstrate the practical utility of our approach, a simulated wastewater experiment was conducted using water from the Fyris River (Sweden). It not only showed a near-Nernstian response to MB+ but also revealed a possible method for potentiometric titration of the redox indicator. Our study thus represents a new paradigm for the rational design of ionophores that can rapidly and precisely monitor molecular ions relevant to environmental, biomedical, and other related areas.

  • 33. Raymond, M
    et al.
    Yang, B.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Ozcan, A.
    Lavoie, C.
    Silicide Contact Resistivity and Phase Formation for Extremely Scaled CMOS Device Applications2012Conference paper (Refereed)
  • 34.
    Wen, Chenyu
    et al.
    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.
    Arstila, Kai
    Department of Physics, University of Jyväskylä, Jyvaskylä, Finland.
    Sajavaara, Timo
    Department of Physics, University of Jyväskylä, Jyvaskylä, Finland.
    Zhu, Yu
    IBM Thomas J. Watson Research Center, New York, United States.
    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.
    Generalized Noise Study of Solid-State Nanopores at Low Frequencies2017In: ACS Sensors, ISSN 2379-3694, Vol. 2, no 2, p. 300-307Article in journal (Refereed)
    Abstract [en]

    Nanopore technology has been extensively investigated for analysis of biomolecules, and a success story in this field concerns DNA sequencing using a nanopore chip featuring an array of hundreds of biological nanopores (BioNs). Solid-state nanopores (SSNs) have been explored to attain longer lifetime and higher integration density than what BioNs can offer, but SSNs are generally considered to generate higher noise whose origin remains to be confirmed. Here, we systematically study lowfrequency (including thermal and flicker) noise characteristics of SSNs measuring 7 to 200 nm in diameter drilled through a 20-nmthick SiNx membrane by focused ion milling. Both bulk and surface ionic currents in the nanopore are found to contribute to the flicker noise, with their respective contributions determined by salt concentration and pH in electrolytes as well as bias conditions. Increasing salt concentration at constant pH and voltage bias leads to increase in the bulk ionic current and noise therefrom. Changing pH at constant salt concentration and current bias results in variation of surface charge density, and hence alteration of surface ionic current and noise. In addition, the noise from Ag/AgCl electrodes can become predominant when the pore size is large and/or the salt concentration is high. Analysis of our comprehensive experimental results leads to the establishment of a generalized nanopore noise model. The model not only gives an excellent account of the experimental observations, but can also be used for evaluation of various noise components in much smaller nanopores currently not experimentally available.

  • 35.
    Wen, Chenyu
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Uppsala University.
    Zeng, Shuangshuang
    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.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Scheicher, Ralph
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    On nanopore DNA sequencing by signal and noise analysis of ionic current2016In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 27, article id 215502Article in journal (Refereed)
    Abstract [en]

    DNA sequencing, i.e., the process of determining the succession of nucleotides on a DNA strand, has become a standard aid in biomedical research and is expected to revolutionize medicine. With the capability of handling single DNA molecules, nanopore technology holds high promises to become speedier in sequencing at lower cost than what are achievable with the commercially available optics-or semiconductor-based massively parallelized technologies. Despite tremendous progress made with biological and solid-state nanopores, high error rates and large uncertainties persist with the sequencing results. Here, we employ a nano-disk model to quantitatively analyze the sequencing process by examining the variations of ionic current when a DNA strand translocates a nanopore. Our focus is placed on signal-boosting and noise-suppressing strategies in order to attain the single-nucleotide resolution. Apart from decreasing pore diameter and thickness, it is crucial to also reduce the translocation speed and facilitate a stepwise translocation. Our best-case scenario analysis points to severe challenges with employing plain nanopore technology, i.e., without recourse to any signal amplification strategy, in achieving sequencing with the desired single-nucleotide resolution. A conceptual approach based on strand synthesis in the nanopore of the translocating DNA from single-stranded to double-stranded is shown to yield a 10-fold signal amplification. Although it involves no advanced physics and is very simple in mathematics, this simple model captures the essence of nanopore sequencing and is useful in guiding the design and operation of nanopore sequencing.

  • 36.
    Wen, Chenyu
    et al.
    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.
    Physical Model for Rapid and Accurate Determination of Nanopore Size via Conductance Measurement2017In: ACS SENSORS, ISSN 2379-3694, Vol. 2, no 10, p. 1523-1530Article in journal (Refereed)
    Abstract [en]

    Nanopores have been explored for various biochemical and nanoparticle analyses, primarily via characterizing the ionic current through the pores. At present, however, size determination for solid-state nanopores is experimentally tedious and theoretically unaccountable. Here, we establish a physical model by introducing an effective transport length, L (eff) that measures, for a symmetric nanopore, twice the distance from the center of the nanopore where the electric field is the highest to the point along the nanopore axis where the electric field falls to e-(1)of this maximum. By G = sigma(s0)/L-eff, a simple expression S-0=/(G, sigma, h, beta) is derived to algebraically correlate minimum nanopore cross-section area S (0)to nanopore conductance G, electrolyte conductivity a, and membrane thickness h with (3 to denote pore shape that is determined by the pore fabrication technique. The model agrees excellently with experimental results for nanopores in graphene, single-layer MoS2, and ultrathin SiNx films. The generality of the model is verified by applying it to micrometer-size pores.

  • 37.
    Wu, Jiyue
    et al.
    Queen Mary Univ London, Sch Engn & Mat Sci, Mile End Rd, London E1 4NS, England.
    Mahajan, Amit
    Queen Mary Univ London, Sch Engn & Mat Sci, Mile End Rd, London E1 4NS, England.
    Riekehr, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Hangfeng
    Queen Mary Univ London, Sch Biol & Chem Sci, Mile End Rd, London E1 4NS, England.
    Yang, Bin
    Univ Chester, Fac Sci & Engn, Dept Elect & Elect Engn, Thornton Sci Pk, Chester CH2 4NU, Cheshire, England.
    Meng, Nan
    Queen Mary Univ London, Sch Engn & Mat Sci, Mile End Rd, London E1 4NS, England.
    Zhang, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Yan, Haixue
    Queen Mary Univ London, Sch Engn & Mat Sci, Mile End Rd, London E1 4NS, England.
    Perovskite Sr-x(Bi1-xNa0.97-xLi0.03)(0.5)TiO3 ceramics with polar nano regions for high power energy storage2018In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 50, p. 723-732Article in journal (Refereed)
    Abstract [en]

    Dielectric capacitors are very attractive for high power energy storage. However, the low energy density of these capacitors, which is mainly limited by the dielectric materials, is still the bottleneck for their applications. In this work, lead-free single-phase perovskite Srx(Bi1-xNa0.97-xLi0.03)(0.5)TiO3 (x = 0.30 and 0.38) bulk ceramics, prepared using solid-state reaction method, were carefully studied for the dielectric capacitor application. Polar nano regions (PNRs) were created in this material using co-substitution at A-site to enable relaxor behaviour with low remnant polarization (P-r) and high maximum polarization (P-max). Moreover, P-max was further increased due to the electric field induced reversible phase transitions in nano regions. Comprehensive structural and electrical studies were performed to confirm the PNRs and reversible phase transitions. And finally a high energy density (1.70 J/cm(3)) with an excellent efficiency (87.2%) was achieved using the contribution of field-induced rotations of PNRs and PNR-related reversible transitions in this material, making it among the best performing lead-free dielectric ceramic bulk material for high energy storage.

  • 38.
    Zhang, Da
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Must, Indrek
    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.
    Xu, Xingxing
    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.
    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.
    Direct assessment of solid–liquid interface noise in ion sensing using a differentialmethod2016In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 108, no 15, article id 151603Article in journal (Refereed)
    Abstract [en]

    This letter presents a microelectrode cell dedicated to direct assessment of the solid-liquid interface noise without recourse to a reference electrode. In the present design, two identical TiN electrodes of various sizes are used for differential measurements in KCl-based electrolytes. Measured noise of the TiN vertical bar electrolyte system is found to be of thermal nature. Scaling inversely with electrode area, the noise is concluded to mainly arise from the solid-liquid interface. This noise is comparable to or larger than that of the state-of-the-art MOSFETs. Therefore, its influence cannot be overlooked for the design of future ion sensors.

  • 39.
    Zhang, Da
    et al.
    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, United States.
    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.
    An impedance model for the low-frequency noise originating from the dynamic hydrogen ion reactivity at the solid/liquid interface2017In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 254, p. 363-369Article in journal (Refereed)
    Abstract [en]

    Understanding the dynamics of hydrogen ion reactivity at the solid/liquid interface is of paramount importance for applications involving ion sensing in electrolytes. However, the correlation of this interfacial process to noise generation is poorly characterized. Here, the relationship is unveiled by characterizing the interfacial process with impedance spectroscopy assisted by a dedicated electrochemical impedance model. The model incorporates both thermodynamic and kinetic properties of the amphoteric hydrogen ion site-binding reactions with the surface OH groups. It further takes into consideration the distributed nature of the characteristic energy of the binding sites. The simulated impedance matches the experimental data better with an energy distribution of the kinetic parameters than with that of the thermodynamic ones. Since the potentiometric low-frequency noise (LFN) originating from the solid/liquid interface correlates excellently with the real part of its electrochemical impedance spectrum, this work establishes a method for evaluating sensing surface quality aimed at mitigating LFN.

    The full text will be freely available from 2019-07-16 10:34
    The full text will be freely available from 2019-07-16 10:36
  • 40.
    Zhang, Da
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics. Uppsala University.
    Solomon, Paul
    IBM T. J. Watson Research Center, Yorktown Heights, New York.
    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.
    Correlation of Low-Frequency Noise to the Dynamic Properties of the Sensing Surface in Electrolytes2017In: ACS Sensors, E-ISSN 2379-3694, Vol. 2, no 8, p. 1160-1166Article in journal (Refereed)
    Abstract [en]

    Low-frequency noise (LFN) is of significant implications in ion sensing. As a primary component of LFN for ion sensing in electrolytes, the solid/liquid interfacial noise remains poorly explored especially regarding its relation to the surface binding/debinding dynamic properties. Here, we employ impedance spectroscopy to systematically characterize this specific noise component for its correlation to the dynamic properties of surface protonation (i.e., hydrogen binding) and deprotonation (i.e., hydrogen debinding) processes. This correlation is facilitated by applying our recently developed interfacial impedance model to ultrathin TiO2 layers grown by means of atomic layer deposition (ALD) on a TiN metallic electrode. With an excellent fitting of the measured noise power density spectra by the model for the studied TiO2 layers, we are able to extract several characteristic dynamic parameters for the TiO2 sensing surface. The observed increase of noise with TiO2 ALD cycles can be well accounted for with an increased average binding site density. This study provides insights into how detailed surface properties may affect the noise performance of an ion sensor operating in electrolytes.

  • 41.
    Zhang, Da
    et al.
    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.
    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.
    Low-frequency noise originating from the dynamic hydrogen ion reactivity at the solid/liquid interface of ion sensors2018Conference paper (Refereed)
    Abstract [en]

    Low-frequency noise (LFN) is of significant implications in ion sensing. As a primary component of LFN for ion sensing in electrolytes, the solid/liquid interfacial noise remains poorly explored especially regarding its relation to the surface binding/de-binding dynamic properties. In this talk, the solid/liquid interfacial noise will first be characterized by direct electrical measurements. It will then be correlated to the dynamic properties of surface protonation (i.e., hydrogen binding) and deprotonation (i.e., hydrogen de-binding) processes using an impedance spectroscopy. Finally we will provide insights into how detailed surface properties may affect the noise performance of an ion sensor operating in electrolytes.

  • 42.
    Zhang, Zhen
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Lu, Jun
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Qiu, Zhijun
    Hellstrom, Per-Erik
    Östling, Mikael
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Performance fluctuation of FinFETs with Schottky barrier source/drain2008In: IEEE Electron Device Letters, ISSN 0741-3106, E-ISSN 1558-0563, Vol. 29, no 5, p. 506-508Article in journal (Refereed)
    Abstract [en]

    A considerable performance fluctuation of FinFETs featuring PtSi-based Schottky barrier source/drain is found. The Fin-channels measure 27-nm tall and 35-nm wide. Investigation of similarly processed transistors of broad gate-widths reveals a large variation in the position of the PtSi/Si interface with reference to the gate edge along the gate width. This variation suggests an uneven underlap between the PtSi and the gate from device to device for the FinFETs, since essentially only one silicide grain would be in contact with each Fin-channel at the PtSi/Si interface. The size of the underlap is expected to sensitively affect the performance of the FinFETs.

  • 43.
    Zhang, Zhen
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Shi-Li, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Bin, Yang
    Yu, Zhu
    Stephen, M. Rossnagel
    Simon, Gaudet
    Andrew, J. Kellock
    Jean, Jordan-Sweet
    Christian, Lavoie
    Morphological stability and specific resistivity of sub-10 nm silicide films of Ni[sub 1 - x]Pt[sub x] on Si substrate2010In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 96, no 7, p. 071915-Article in journal (Refereed)
    Abstract [en]

    This letter studies the morphological stability and specific resistivity of sub-10 nm silicide films of Ni, Ni0.95Pt0.05, and Ni0.9Pt0.1 formed on Si(100) substrate. When the deposited metal films are below 1 to 4 nm in thickness depending on the Pt content, the resultant silicide films tend to become epitaxially aligned to the Si substrate and hence exhibit an extraordinary morphological stability up to 800 °C. The presence of Pt in the silicides increases the film resistivity through alloy scattering, but alleviates, owing to a reduced electron mean free path, the frequently encountered sharp increase in resistivity in the sub-10 nm regime.

  • 44.
    Zhang, Zhen
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Yang, Bin
    Zhu, Yu
    Gaudet, Simon
    Rossnagel, Steve
    Kellock, Andrew J.
    Ozcan, Ahmet
    Murray, Conal
    Desjardins, Patrick
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Jordan-Sweet, Jean
    Lavoie, Christian
    Exploitation of a self-limiting process for reproducible formation of ultrathin Ni1−xPtx silicide films2010In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 97, no 25, p. 252108-Article in journal (Refereed)
    Abstract [en]

    This letter reports on a process scheme to obtain highly reproducible Ni1−xPtx silicide films of 3–6 nm thickness formed on a Si(100) substrate. Such ultrathin silicide films are readily attained by sputter deposition of metal films, metal stripping in wet chemicals, and final silicidation by rapid thermal processing. This process sequence warrants an invariant amount of metal intermixed with Si in the substrate surface region independent of the initial metal thickness, thereby leading to a self-limiting formation of ultrathin silicide films. The crystallographic structure, thickness, uniformity, and morphological stability of the final silicide films depend sensitively on the initial Pt fraction.

  • 45.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    A METHOD TO FORM SILICIDE CONTACT IN TRENCHES2012Patent (Other (popular science, discussion, etc.))
  • 46.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    A NOVEL DUAL SILICIDE PROCESS2013Patent (Other (popular science, discussion, etc.))
  • 47.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    A SCHOTTKY JUNCTION SI NANOWIRE/NANOBELT FIELD-EFFECT BIO-SENSOR/MOLECULE DETECTOR2010Patent (Other (popular science, discussion, etc.))
  • 48.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Advanced contact technology: from material properties to device applications2012Conference paper (Refereed)
  • 49.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    CARBON-DOPED CAP FOR A RAISED ACTIVE SEMICONDUCTOR REGION2013Patent (Other (popular science, discussion, etc.))
  • 50.
    Zhen, Zhang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    COLORIMETRIC RADIATION DOSIMETRY BASED ON FUNCTIONAL POLYMER AND GOLD NANOPARTICLE HYBRID2013Patent (Other (popular science, discussion, etc.))
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