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Blom, Hans-Olof
Publications (10 of 34) Show all publications
Marchack, N., Kim, T., Blom, H.-O. & Chang, J. P. (2015). In-situ etch rate study of HfxLayOz in Cl-2/BCl3 plasmas using the quartz crystal microbalance. Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, 33(3), Article ID 031305.
Open this publication in new window or tab >>In-situ etch rate study of HfxLayOz in Cl-2/BCl3 plasmas using the quartz crystal microbalance
2015 (English)In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 33, no 3, article id 031305Article in journal (Refereed) Published
Abstract [en]

The etch rate of HfxLayOz films in Cl-2/BCl3 plasmas was measured in-situ in an inductively coupled plasma reactor using a quartz crystal microbalance and corroborated by cross-sectional SEM measurements. The etch rate depended on the ion energy as well as the plasma chemistry. In contrast to other Hf-based ternary oxides, the etch rate of HfxLayOz films was higher in Cl-2 than in BCl3. In the etching of Hf0.25La0.12O0.63, Hf appeared to be preferentially removed in Cl-2 plasmas, per surface compositional analysis by x-ray photoelectron spectroscopy and the detection of HfCl3 generation in mass spectroscopy. These findings were consistent with the higher etch rate of Hf0.25La0.12O0.63 than that of La2O3.

National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-257038 (URN)10.1116/1.4914132 (DOI)000355741800009 ()
Available from: 2015-06-29 Created: 2015-06-29 Last updated: 2017-12-04Bibliographically approved
Martin, R. M., Blom, H.-O. & Chang, J. . (2009). Plasma Etching of Hf-based High-k Thin Films. Part II, Ion Enhanced Surface Reaction Mechanisms. Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, 27(2), 217-223
Open this publication in new window or tab >>Plasma Etching of Hf-based High-k Thin Films. Part II, Ion Enhanced Surface Reaction Mechanisms
2009 (English)In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 27, no 2, p. 217-223Article in journal (Refereed) Published
Abstract [en]

The mechanism for ion-enhanced chemical etching of hafnium aluminate thin films in Cl-2/BCl3 plasmas was investigated in this work, specifically how the film composition, ion energy, and plasma chemistry determine their etch rates. Several compositions of Hf1-xAlxOy thin films ranging from pure HfO2 to pure Al2O3 were etched in BCl3/Cl-2 plasmas and their etch rates were found to scale with E-ion in both Cl-2 and BCl3 plasmas. In Cl-2 plasmas, a transition point was observed around 50 eV, where the etch rate was significantly enhanced while the linear dependence toE(ion) was maintained, corresponding to a change in the removal of fully chlorinated to less chlorinated reaction products. In BCl3 plasma, deposition dominates at ion energies below 50 eV, while etching occurs above that energy with an etch rate of three to seven times that in Cl-2. The faster etch rate in BCl3 was attributed to a   change in the dominant ion from Cl-2+ in Cl-2 plasma to BCl2+ in BCl3, which facilitated the formation of more volatile etch products and their removal. The surface chlorination (0-3 at. %) was enhanced with increasing ion energy while the amount of boron on the surface   increases with decreasing ion energy, highlighting the effect of different plasma chemistries on the etch rates, etch product formation, and surface termination.

Keyword
aluminium compounds, hafnium compounds, high-k dielectric thin films, sputter etching, surface chemistry
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-121217 (URN)10.1116/1.3065695 (DOI)000264017500008 ()
Available from: 2010-03-19 Created: 2010-03-19 Last updated: 2017-12-12Bibliographically approved
Liu, J., Mao, Y., Lan, E., Banatao, D. R., Forse, G. J., Lu, J., . . . Chang, J. P. (2008). Generation of Oxide Nanopatterns by Combining Self-Assembly of S-Layer Proteins and Area-Selective Atomic Layer Deposition. Journal of the American Chemical Society, 130(50), 16908-16913
Open this publication in new window or tab >>Generation of Oxide Nanopatterns by Combining Self-Assembly of S-Layer Proteins and Area-Selective Atomic Layer Deposition
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2008 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 130, no 50, p. 16908-16913Article in journal (Refereed) Published
Abstract [en]

We report an effective method to fabricate two-dimensional (2D) periodic oxide nanopatterns using S-layer proteins as a template. Specifically, S-layer proteins with a unit cell dimension of 20 nm were reassembled on silicon substrate to form 2D arrays with ordered pores of nearly identical sizes (9 nm). Octadecyltrichlorosilane (ODTS) was utilized to selectively react with the S-layer proteins, but not the Si surface exposed through the pores defined by the proteins. Because of the different surface functional groups on the ODTS-modified S-layer proteins and Si surface, area-selective atomic layer deposition of metal oxide-based high-k materials, such as hafnium oxide, in the pores was achieved. The periodic metal oxide nanopatterns were generated on Si substrate after selective removal of the ODTS-modified S-layer proteins. These nanopatterns of high-k materials are expected to facilitate further downscaling of logic and memory nanoelectronic devices.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-110870 (URN)10.1021/ja803186e (DOI)000263320400026 ()
Available from: 2009-11-27 Created: 2009-11-27 Last updated: 2017-12-12Bibliographically approved
Sawkar-Mathur, M., Perng, Y.-C., Lu, J., Blom, H.-O., Bargar, J. & Chang, J. P. (2008). The effect of aluminum oxide incorporation on the material and electrical properties of hafnium oxide on Ge. Applied Physics Letters, 93(23), 233501
Open this publication in new window or tab >>The effect of aluminum oxide incorporation on the material and electrical properties of hafnium oxide on Ge
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2008 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 93, no 23, p. 233501-Article in journal (Refereed) Published
Abstract [en]

Hafnium aluminate thin films were synthesized by atomic layer deposition (ALD) to assess the effect of aluminum oxide incorporation on the dielectric/Ge interfacial properties. In these HfxAlyOz thin films, the Hf to Al cation ratio was effectively controlled by changing the ratio of hafnium oxide to aluminum oxide ALD cycles, while their short range order was changed upon increasing aluminum oxide incorporation, as observed by extended x-ray absorption fine structure analysis. The incorporation of aluminum oxide was shown to improve the   electrical characteristics of hafnium oxide/Ge devices, including lower interface state densities and leakage current densities.

Keyword
aluminium compounds, atomic layer deposition, current density, dielectric thin films, elemental semiconductors, EXAFS, germanium, hafnium compounds, interface states, leakage currents, semiconductor-insulator boundaries
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-105880 (URN)10.1063/1.3040311 (DOI)000261699700077 ()
Available from: 2009-06-09 Created: 2009-06-09 Last updated: 2017-12-13Bibliographically approved
Tanner, C. M., Toney, M. F., Lu, J., Blom, H.-O., Sawkar-Mathur, M., Tafesse, M. A. & Chang, J. P. (2007). Engineering epitaxial gamma-Al2O3 gate dielectric films on 4H-SiC. Journal of Applied Physics, 102(10), 104112-104112-6
Open this publication in new window or tab >>Engineering epitaxial gamma-Al2O3 gate dielectric films on 4H-SiC
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2007 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 102, no 10, p. 104112-104112-6Article in journal (Refereed) Published
Abstract [en]

The formation of epitaxial gamma-Al2O3 thin films on 4H-SiC was found to be strongly dependent on the film thickness. An abrupt interface was observed in films up to 200 A thick with an epitaxial relationship of gamma-Al2O3(111)parallel to 4H-SiC(0001) and gamma-Al2O3(4 (4) over bar0)parallel to 4H-SiC(11 (2) over bar0). The in-plane alignment between the film and the substrate is nearly complete for gamma-Al2O3 films up to 115 A thick, but quickly diminishes in thicker films. The films are found to be slightly strained laterally in tension; the strain increases with thickness and then decreases in films thicker than 200 A, indicating strain relaxation which is accompanied by increased misorientation. By controlling the structure of ultrathin Al2O3 films, metal-oxide-semiconductor capacitors with Al2O3 gate dielectrics on 4H-SiC were found to have a very low leakage current density, suggesting suitability of Al2O3 for SiC device integration.

National Category
Natural Sciences Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-12766 (URN)10.1063/1.2812609 (DOI)000251324900074 ()
Available from: 2008-01-18 Created: 2008-01-18 Last updated: 2017-12-11Bibliographically approved
Rangelow, I. W., Ivanov, T., Ivanova, K., Volland, B. E., Grabiec, P., Sarov, Y., . . . Blom, H.-O. (2007). Piezoresistive and self-actuated 128-cantilever arrays for nanotechnology applications. Microelectronic Engineering, 84(5-8), 1260-1264
Open this publication in new window or tab >>Piezoresistive and self-actuated 128-cantilever arrays for nanotechnology applications
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2007 (English)In: Microelectronic Engineering, ISSN 0167-9317, E-ISSN 1873-5568, Vol. 84, no 5-8, p. 1260-1264Article in journal (Refereed) Published
Abstract [en]

A major limitation for future nanotechnology, particularly for bottom-up manufacturing is the non-availability of 2-dimensional massively parallel probe arrays. Scanning proximity probes are uniquely powerful tools for analysis, manipulation and bottom-up synthesis: they are capable of addressing and engineering surfaces at the atomic level and are the key to unlocking the full potential of Nanotechnology. Generic massively parallel intelligent cantilever-probe platforms is demonstrated through a number of existing and ground-breaking techniques. A packaged VLSI NEMS-chip (Very Large Scale Integrated Nano Electro Mechanical System) incorporating 128 proximal probes, fully addressable with control and readout interconnects and advanced software will be presented.

Keyword
piezoresistive micro-cantilever, self-actuated micro-cantilever, cantilever arrays
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-151498 (URN)10.1016/j.mee.2007.01.219 (DOI)000247182500134 ()
Available from: 2011-04-13 Created: 2011-04-12 Last updated: 2017-12-11Bibliographically approved
Tanner, C. M., Sawkar-Mathur, M., Lu, J., Blom, H.-O., Toney, M. F. & Chang, J. P. (2007). Structural properties of epitaxial gamma-Al2O3(111) thin films on 4H-SiC(0001). Applied Physics Letters, 90(6), 061916
Open this publication in new window or tab >>Structural properties of epitaxial gamma-Al2O3(111) thin films on 4H-SiC(0001)
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2007 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 90, no 6, p. 061916-Article in journal (Refereed) Published
Abstract [en]

Al2 O3 thin films were grown on 4H-SiC (0001) by thermal atomic layer deposition and were crystallized to the γ- Al2 O3 phase by rapid thermal annealing in N2 at 1100 °C. The films were found to be chemically stable during processing based on x-ray photoelectron spectroscopy. The change in film structure was initially confirmed by reflection high-energy electron diffraction. As shown by high-resolution transmission electron microscopy images, the abrupt interface of the as-deposited films with the 4H-SiC substrate was preserved during crystallization, indicating no interfacial reaction. Selected area electron diffraction and synchrotron-based x-ray diffraction established an epitaxial relationship of γ- Al2 O3 (111) ∥ 4H-SiC (0001) and in-plane orientation of γ- Al2 O3 (1 1- 0) ∥ 4H-SiC (11 2- 0). No other alumina phases or orientations were observed and no in-plane misorientation was observed in the 27 Å Al2 O3 films. The full width at half maximum of the γ- Al2 O3 (222) rocking curve is 0.056°, indicating a lack of mosaic spread and a high-quality crystalline film. Twinning around the γ- Al2 O3 [111] axis was the only defect observed in these films.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-26526 (URN)10.1063/1.2435978͔ (DOI)000244162300033 ()
Available from: 2008-01-18 Created: 2008-01-18 Last updated: 2017-12-07Bibliographically approved
Tanner, C. M., Lu, J., Blom, H.-O. & Chang, J. P. (2006). Growth of Epitaxial y-Al2O3 Films on 4H-SiC. In: : . Paper presented at American Vacuum Society 53rd National Symposium, San Francisco.
Open this publication in new window or tab >>Growth of Epitaxial y-Al2O3 Films on 4H-SiC
2006 (English)Conference paper, Published paper (Refereed)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-25867 (URN)
Conference
American Vacuum Society 53rd National Symposium, San Francisco
Available from: 2007-04-25 Created: 2007-04-25 Last updated: 2016-07-12
Martin, R. M., Blom, H.-O. & Chang, J. P. (2006). Ion-Enhanced Plasma Etching of Hafnium Aluminates in Chlorine Based Plasmas. In: : . Paper presented at Proc American Vacuum Society 53rd National Symposium, San Francisco.
Open this publication in new window or tab >>Ion-Enhanced Plasma Etching of Hafnium Aluminates in Chlorine Based Plasmas
2006 (English)Conference paper, Published paper (Refereed)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-23556 (URN)
Conference
Proc American Vacuum Society 53rd National Symposium, San Francisco
Available from: 2007-01-30 Created: 2007-01-30 Last updated: 2016-06-22
Van, T. T., Hoang, J., Osrumov, R., Wang, K. L., Barger, J. R., Lu, J. & Blom, H.-O. (2006). Nanostructure and Temperature-dependent Photoluminescence of Er-doped Y2O3 Thin Films for Micro-optoelectronic Integrated Circuits. Journal of Applied Physics, 100(7), 073512
Open this publication in new window or tab >>Nanostructure and Temperature-dependent Photoluminescence of Er-doped Y2O3 Thin Films for Micro-optoelectronic Integrated Circuits
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2006 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 100, no 7, p. 073512-Article in journal (Refereed) Published
Abstract [en]

The nanostructure and photoluminescence of polycrystalline Er-doped Y2O3 thin films, deposited by radical-enhanced atomic layer deposition (ALD), were investigated in this study. The controlled distribution of erbium separated by layers of Y2O3, with erbium concentrations varied from 6 to 14 at. %, was confirmed by elemental electron energy loss spectroscopy (EELS) mapping of Er M-4 and M-5. This unique feature is characteristic of the alternating radical-enhanced ALD of Y2O3 and Er2O3. The results are also consistent with the extended x-ray absorption fine structure (EXAFS) modeling of the Er distribution in the Y2O3 thin films, where the EXAFS data were best fitted to a layer-like structure. X-ray diffraction (XRD) and selected-area electron diffraction (SAED) patterns revealed a preferential film growth in the [111] direction, showing a lattice contraction with increasing Er doping concentration, likely due to Er3+ of a smaller ionic radius replacing the slightly larger Y3+. Room-temperature photoluminescence characteristic of the Er3+ intra-4f transition at 1.54 mu m was observed for the 500 A, 8 at. % Er-doped Y2O3 thin film, showing various well-resolved Stark features due to different spectroscopic transitions from the I-4(13/2)-> I-4(15/2) energy manifold. The result indicates the proper substitution of Y3+ by Er3+ in the Y2O3 lattice, consistent with the EXAFS and XRD analyses. Thus, by using radical-enhanced ALD, a high concentration of optically active Er3+ ions can be incorporated in Y2O3 with controlled distribution at a low temperature, 350 degrees C, making it possible to observe room-temperature photoluminescence for fairly thin films (similar to 500-900 A) without a high temperature annealing.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-23525 (URN)10.1063/1.2349477 (DOI)000241248000023 ()
Available from: 2007-04-25 Created: 2007-04-25 Last updated: 2017-12-07Bibliographically approved
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