Browsing by Author "Hong, M."

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Al(2)O(3)/Ga(2)O(3)(Gd(2)O(3)) passivation on In(0.20)Ga(0.80)As/GaAs-structural intactness with high-temperature annealing
(2010-04-07)
Lee, Y. J.
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Lee, C. H.
;
Tung, L. T.
;
Chiang, T. H.
;
Lai, T. Y.
Molecular beam epitaxy grown Al(2)O(3)/Ga(2)O(3)(Gd(2)O(3))/In(0.20)Ga(0.80)As/GaAs has been rapidly thermal annealed to 850 degrees C in N(2). The hetero-structure remained intact, with the In(0.20)Ga(0.80)As/GaAs interface being free of misfit dislocation and In(0.20)Ga(0.80)As strained, as observed by high-resolution transmission electron microscopy and high-resolution x-ray diffraction using synchrotron radiation. Excellent capacitance-voltage characteristics as well as low electrical leakages were obtained. These structural and electrical results demonstrate that employing Ga(2)O(3)(Gd(2)O(3)) as a dielectric with an in situ Al(2)O(3) capping layer efficiently protects strained InGaAs layers from relaxing and volatilizing during rapid thermal annealing to 850 degrees C, important for fabricating inversion-channel InGaAs metal-oxide-semiconductor field-effect-transistors, a candidate for beyond the 16 nm node complementary MOS technology.
Al2O3/Ga2O3(Gd2O3) passivation on In0.20Ga0.80As/GaAs-structural intactness with high-temperature annealing
(2010-04-07)
Lee, Y. J.
;
Lee, C. H.
;
Tung, L. T.
;
Chiang, T. H.
;
Lai, T. Y.
Molecular beam epitaxy grown Al2O3/Ga2O3(Gd2O3)/In0.20Ga0.80As/GaAs has been rapidly thermal annealed to 850 degrees C in N-2. The hetero-structure remained intact, with the In0.20Ga0.80As/GaAs interface being free of misfit dislocation and In0.20Ga0.80As strained, as observed by high-resolution transmission electron microscopy and high-resolution x-ray diffraction using synchrotron radiation. Excellent capacitance-voltage characteristics as well as low electrical leakages were obtained. These structural and electrical results demonstrate that employing Ga2O3(Gd2O3) as a dielectric with an in situ Al2O3 capping layer efficiently protects strained InGaAs layers from relaxing and volatilizing during rapid thermal annealing to 850 degrees C, important for fabricating inversion-channel InGaAs metal-oxide-semiconductor field-effect-transistors, a candidate for beyond the 16 nm node complementary MOS technology.
Correlation between crystal structure and photoluminescence for epitaxial ZnO on Si(111) using a gamma-Al(2)O(3) buffer layer
(2008-03-21)
Liu, W-R
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Li, Y-H
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Hsieh, W. F.
;
Hsu, C-H
;
Lee, W. C.
High-quality ZnO epitaxial films were grown by pulsed-laser deposition on Si (1 1 1) substrates with a thin. gamma-Al(2)O(3) buffer layer. The epitaxial. gamma-Al(2)O(3) buffer layer consists of two (1 1 1) oriented domains rotated 60. from each other against the surface normal, which yields the in-plane epitaxial relationship (1 0 0)ZnO
Defect density reduction of the Al(2)O(3)/GaAs(001) interface by using H(2)S molecular beam passivation
(2011-10-01)
Merckling, C.
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Chang, Y. C.
;
Lu, C. Y.
;
Penaud, J.
;
Brammertz, G.
The integration of higher carrier mobility materials to increase drive current capability in the next CMOS generations is required for device scaling. But a fundamental issue regarding the introduction of high-mobility III-V in CMOS is the electrical passivation of the interface with the high-kappa gate dielectric. In this work, we show that in situ H(2)S surface treatment on GaAs(001) leads to a stable and reorganized oxide/III-V interface. The exposition of the GaAs surface is monitored in situ by RHEED and the interface is characterized by XPS analyses. Finally, MOS capacitors are fabricated to extract interface state density over the band gap. These results highlight a promising re-interest in chalcogenide passivation of III-V surfaces for CMOS applications. (C) 2011 Elsevier B.V. All rights reserved.
Defect density reduction of the Al2O3/GaAs(001) interface by using H2S molecular beam passivation
(2011-10-01)
Merckling, C.
;
Chang, Y. C.
;
Lu, C. Y.
;
Penaud, J.
;
Brammertz, G.
The integration of higher carrier mobility materials to increase drive current capability in the next CMOS generations is required for device scaling. But a fundamental issue regarding the introduction of high-mobility III-V in CMOS is the electrical passivation of the interface with the high-kappa gate dielectric. In this work, we show that in situ H2S surface treatment on GaAs(001) leads to a stable and reorganized oxide/III-V interface. The exposition of the GaAs surface is monitored in situ by RHEED and the interface is characterized by XPS analyses. Finally, MOS capacitors are fabricated to extract interface state density over the band gap. These results highlight a promising re-interest in chalcogenide passivation of III-V surfaces for CMOS applications. (C) 2011 Elsevier B.V. All rights reserved.
Domain Matching Epitaxial Growth of High-Quality ZnO Film Using a Y(2)O(3) Buffer Layer on Si (111)
(2009-01-01)
Liu, W. -R.
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Li, Y. -H.
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Hsieh, W. F.
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Hsu, C. -H.
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Lee, W. C.
High-quality ZnO epitaxial films have been grown by pulsed-laser deposition on Si (111) substrates using a nanothick high-k oxide Y(2)O(3) buffer layer. Determined by X-ray diffraction and transmission electron microscopy, the epitaxial relationship between ZnO and Y(2)O(3) follows (0001)< 2 (1) over bar(1) over bar0 >(ZnO)parallel to(111)< 10 (1) over bar > Y(2)O(3). ZnO lattice aligns with the hexagonal O sublattice in Y(2)O(3) and the interfacial structure can be well described by domain matching epitaxy with 7 or 8 ZnO {11 (2) over bar0} planes matching 6 or 7 {4 (4) over bar0} planes Of Y(2)O(3) and lead to a significant reduction of residual strain. Superior optical properties were obtained even for ZnO films as thin as 0.21 mu m from photoluminescence results.
Domain Matching Epitaxial Growth of High-Quality ZnO Film Using a Y2O3 Buffer Layer on Si (111)
(2009-01-01)
Liu, W. -R.
;
Li, Y. -H.
;
Hsieh, W. F.
;
Hsu, C. -H.
;
Lee, W. C.
High-quality ZnO epitaxial films have been grown by pulsed-laser deposition on Si (111) substrates using a nanothick high-k oxide Y2O3 buffer layer. Determined by X-ray diffraction and transmission electron microscopy, the epitaxial relationship between ZnO and Y2O3 follows (0001)< 2 (1) over bar(1) over bar0 >(ZnO)parallel to(111)< 10 (1) over bar > Y2O3. ZnO lattice aligns with the hexagonal O sublattice in Y2O3 and the interfacial structure can be well described by domain matching epitaxy with 7 or 8 ZnO {11 (2) over bar0} planes matching 6 or 7 {4 (4) over bar0} planes Of Y2O3 and lead to a significant reduction of residual strain. Superior optical properties were obtained even for ZnO films as thin as 0.21 mu m from photoluminescence results.
Epitaxial stabilization of a monoclinic phase in Y(2)O(3) films on c-plane GaN
(2011-05-15)
Chang, W. H.
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Chang, P.
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Lee, W. C.
;
Lai, T. Y.
;
Kwo, J.
Nanometer-thick Y(2)O(3) films were grown epitaxially on GaN (0 0 0 1) using molecular beam epitaxy (MBE). The structures of the oxide films were studied in situ by reflection high energy electron diffraction (RHEED) during the growth and ex situ by high resolution X-ray diffraction using synchrotron radiation. At atmospheric pressure. Y(2)O(3) exists in either cubic or hexagonal structure. For the first time, the high-pressure monoclinic phase of Y(2)O(3), stabilized by epitaxy, was prepared and preserved under atmospheric pressure. The electrical characterization carried out on the Y(2)O(3)/GaN metal-oxide-semiconductor (MOS) capacitors showed a leakage current density of similar to 3.3 x 10(-6) A/cm(2) at 1.5 MV/cm, which remained almost the same after 800 degrees C annealing. A dielectric constant of similar to 20 and a hysteresis of similar to 250 mV were deduced from the capacitance-voltage (C-V) curves for the epitaxial monoclinic Y(2)O(3). (C) 2010 Elsevier B.V. All rights reserved.
Epitaxial stabilization of a monoclinic phase in Y2O3 films on c-plane GaN
(2011-05-15)
Chang, W. H.
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Chang, P.
;
Lee, W. C.
;
Lai, T. Y.
;
Kwo, J.
Nanometer-thick Y2O3 films were grown epitaxially on GaN (0 0 0 1) using molecular beam epitaxy (MBE). The structures of the oxide films were studied in situ by reflection high energy electron diffraction (RHEED) during the growth and ex situ by high resolution X-ray diffraction using synchrotron radiation. At atmospheric pressure. Y2O3 exists in either cubic or hexagonal structure. For the first time, the high-pressure monoclinic phase of Y2O3, stabilized by epitaxy, was prepared and preserved under atmospheric pressure. The electrical characterization carried out on the Y2O3/GaN metal-oxide-semiconductor (MOS) capacitors showed a leakage current density of similar to 3.3 x 10(-6) A/cm(2) at 1.5 MV/cm, which remained almost the same after 800 degrees C annealing. A dielectric constant of similar to 20 and a hysteresis of similar to 250 mV were deduced from the capacitance-voltage (C-V) curves for the epitaxial monoclinic Y2O3. (C) 2010 Elsevier B.V. All rights reserved.
Exciton Localization of High-Quality ZnO/MgxZn1-x Multiple Quantum Wells on Si (111) with a Y2O3 Buffer Layer
(2018-08-01)
Liu, Wei-Rein
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Huang, Wei-Lun
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Wu, Yung-Chi
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Lai, Liang-Hsun
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Hsu, Chia-Hung
We report the structural and optical properties of ten-period ZnO/MgxZn1-x multiple quantum wells (MQWs) prepared on the most widely used semiconductor material, Si. The introduction of a nanometer thick high-k Y2O3 transition layer between Si (111) substrate and a ZnO buffer layer significantly improves the structural perfection of the MQWs grown on top of it. The high structural quality of the ZnO/MgxZn1-xO MQWs is evidenced by the appearance of pronounced high order satellite peaks in X-ray crystal truncation rods; high resolution cross-sectional transmission electron microscopy images also confirmed the regularly arranged well and barrier layers. When the well width is less than similar to 2.7 nm, the quantum-confined Stark effect in MQWs can be negligible. Not only the increasing exciton-binding energy but also reducing exciton-phonon coupling determined in temperature-dependent photoluminescence spectra indicate quantum-size effect. Our results demonstrate that ZnO/MgxZn1-xO MQWs integrated on Si have great potential in UV optoelectronic device applications.
Growth and structural characteristics of GaN/AlN/nanothick gamma-Al(2)O(3)/Si (111)
(2008-05-01)
Lee, W. C.
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Lee, Y. J.
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Tung, L. T.
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Wu, S. Y.
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Lee, C. H.
The authors report on the growth of GaN by nitrogen plasma-assisted molecular beam epitaxy (MBE) on a 2 in. Si (111) substrates with a nanothick (similar to 4.8 nm thick) gamma-Al(2)O(3) as a template/buffer. A thin layer of MBE-AlN similar to 40 nm thick was inserted prior to the growth of GaN. High-resolution transmission electron microscopy (HR-TEM) and high-resolution x-ray diffraction studies indicated that both of the nanothick gamma-Al(2)O(3) and AlN are a single crystal. Reflection high-energy electron diffraction, high-resolution x-ray scattering using synchrotron radiation, and cross-sectional HR-TEM measurements indicated an orientation relationship of GaN(0002)parallel to AlN(0002)parallel to gamma-Al(2)O(3)(111)parallel to Si(111) and GaN[10-10]parallel to AlN[10-10]parallel to gamma-Al(2)O(3)[2-1-1]parallel to Si[2-1-1]. A dislocation density of 5x(10(8)-10(9))/cm(2) in the GaN similar to 0.5 mu m thick was determined using cross-sectional TEM images under weak-beam dark-field conditions. (C) 2008 American Vacuum Society.
H(2)S molecular beam passivation of Ge(001)
(2011-04-01)
Merckling, C.
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Chang, Y. C.
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Lu, C. Y.
;
Penaud, J.
;
El-Kazzi, M.
A fundamental issue regarding the introduction of high-mobility Ge channels in CMOS circuits is the electrical passivation of the interface with the high-k gate dielectric. In this paper, we investigate the passivation of p-Ge(0 0 1) using molecular H(2)S. The modification of the semiconductor surface is monitored in situ by RHEED and the interface is characterized by XPS analyses. MOS capacitors are fabricated to extract interface state density, and finally we demonstrate the efficiency of the passivation scheme using a combination with an ultra thin Al interlayer. (C) 2010 Elsevier B.V. All rights reserved.
H2S molecular beam passivation of Ge(001)
(2011-04-01)
Merckling, C.
;
Chang, Y. C.
;
Lu, C. Y.
;
Penaud, J.
;
El-Kazzi, M.
A fundamental issue regarding the introduction of high-mobility Ge channels in CMOS circuits is the electrical passivation of the interface with the high-k gate dielectric. In this paper, we investigate the passivation of p-Ge(0 0 1) using molecular H2S. The modification of the semiconductor surface is monitored in situ by RHEED and the interface is characterized by XPS analyses. MOS capacitors are fabricated to extract interface state density, and finally we demonstrate the efficiency of the passivation scheme using a combination with an ultra thin Al interlayer. (C) 2010 Elsevier B.V. All rights reserved.
High-quality nanothick single-crystal Y(2)O(3) films epitaxially grown on Si (111): Growth and structural characteristics
(2008-05-01)
Lee, Y. J.
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Lee, W. C.
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Nieh, C. W.
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Yang, Z. K.
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Kortan, A. R.
High-quality single-crystal nanothick Y(2)O(3) films have been grown epitaxially on Si (111) despite a lattice mismatch of 2.4%. The films were electron beam evaporated from pure compacted powder Y(2)O(3) target in ultrahigh vacuum. Y(2)O(3) 3 nm thick exhibited a bright, sharp, streaky reconstructed (4x4) reflection high energy electron diffraction pattern. Structural studies carried out by x-ray diffraction with synchrotron radiation and high-resolution transmission electron microscopy show that the films have the cubic bixbyite phase with a remarkably uniform thickness and high structural perfection. Two Y(2)O(3) domains of B-type Y(2)O(3) [2 (1) over bar(1) over bar]parallel to Si[11 (2) over bar] and A-type Y(2)O(3) [2 (1) over bar(1) over bar]parallel to Si[2 (1) over bar(1) over bar] coexist in the initial film growth with B type predominating over A type in thicker films as studied using x-ray diffraction. The narrow full width at half maximum of 0.014 degrees in the omega-rocking curve is the characteristic of excellent crystalline films. High-resolution transmission electron microscopy and fast Fourier transform analysis show atomically sharp interface and strain relaxation in thicker films. (C) 2008 American Vacuum Society.
MBE-Enabling technology beyond Si CMOS
(2011-05-15)
Chang, P.
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Lee, W. C.
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Lin, T. D.
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Hsu, C. H.
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Kwo, J.
Achievement of low interfacial densities of states, small equivalent oxide thickness, high kappa values, and thermal stability at high temperatures in the high kappa dielectrics on high carrier mobility semiconductors, the leading candidates for technology beyond Si CMOS, has been made using MBE. This paper reviews our recent advances in meeting the unprecedented demands in materials and physics for the new technology. Moreover, self-aligned inversion-channel InGaAs and Ge MOSFETs using MBE-Ga(2)O(3)(Gd(2)O(3)) as the gate dielectric are compared favorably with those using the gate dielectrics made from other thin film techniques. (C) 2010 Elsevier B.V. All rights reserved.
Structural Characteristics of Nanometer Thick Gd(2)O(3) Films Grown on GaN (0001)
(2010-12-01)
Chang, W. H.
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Chang, P.
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Lai, T. Y.
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Lee, Y. J.
;
Kwo, J.
High-quality Gd(2)O(3) epi-films 5-20 nm thick have been grown on GaN (0001) using molecular beam epitaxy A detailed structural investigation was carried out by in situ reflection high energy electron diffraction cross sectional transmission electron microscopy, and X-ray scattering using a synchrotron radiation source The films consist of the high temperature monoclinic (m) phase with six rotational domains which can be easily mistaken for being the hexagonal phase All the domains follow the m-Gd(2)O(3) ((2) over bar 01)< 020 > parallel to GaN (0001) < 11<(2)over bar>0 > orientational relationship
Structural Characteristics of Nanometer Thick Gd2O3 Films Grown on GaN (0001)
(2010-12-01)
Chang, W. H.
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Chang, P.
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Lai, T. Y.
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Lee, Y. J.
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Kwo, J.
High-quality Gd2O3 epi-films 5-20 nm thick have been grown on GaN (0001) using molecular beam epitaxy A detailed structural investigation was carried out by in situ reflection high energy electron diffraction cross sectional transmission electron microscopy, and X-ray scattering using a synchrotron radiation source The films consist of the high temperature monoclinic (m) phase with six rotational domains which can be easily mistaken for being the hexagonal phase All the domains follow the m-Gd2O3 ((2) over bar 01)< 020 > parallel to GaN (0001) < 11<(2)over bar>0 > orientational relationship
Structure of HfO2 films epitaxially grown on GaAs(001)
(2006-09-18)
Hsu, C. -H.
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Chang, P.
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Lee, W. C.
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Yang, Z. K.
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Lee, Y. J.
High-quality HfO2 films of technologically important thickness ranging from 1.8 to 17 nm have been grown epitaxially on GaAs (001) by molecular beam epitaxy. Thorough structural and morphological investigations were carried out by x-ray scattering and high-resolution transmission electron microscopy. The films exhibit an atomically sharp interface with the substrate and are of a monoclinic phase with predominant (001)-plane epitaxy between the HfO2 films and GaAs, in spite of a large lattice mismatch of > 8.5%.
The Growth of an Epitaxial ZnO Film on Si(111) with a Gd(2)O(3)(Ga(2)O(3)) Buffer Layer
(2011-07-01)
Lin, B. H.
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Liu, W. R.
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Yang, S.
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Kuo, C. C.
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Hsu, C. -H.
High-quality (0001)-oriented ZnO epitaxial films have been grown by pulsed laser deposition on Si(111) buffered with a nanometer-thick Gd(2)O(3)(Ga(2)O(3)), GGO, layer. The structural characteristics of the ZnO epi-layers were studied by X-ray diffraction and transmission electron microscopy (TEM). The in-plane epitaxial relationship between the wurtzite ZnO, cubic GGO, and cubic Si follows {10 (1) over bar0}(ZNO)parallel to{4 (22) over bar}(Gd2O3)parallel to{(4) over bar 22}(Si) and the ZnO/GGO interface can be described by the domain matching epitaxy. TEM contrast analysis reveals that the major defect structures in the ZnO films are edge-type threading dislocations and intrinsic basal plane stacking faults. All the ZnO epi-films studied are under a tensile biaxial strain, but no cracks were found. Temperature-dependent photoluminescence results show the excellent optical properties of the obtained ZnO layers, and the origins of the spectral features are discussed.
The Growth of an Epitaxial ZnO Film on Si(111) with a Gd2O3(Ga2O3) Buffer Layer
(2011-07-01)
Lin, B. H.
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Liu, W. R.
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Yang, S.
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Kuo, C. C.
;
Hsu, C. -H.
High-quality (0001)-oriented ZnO epitaxial films have been grown by pulsed laser deposition on Si(111) buffered with a nanometer-thick Gd2O3(Ga2O3), GGO, layer. The structural characteristics of the ZnO epi-layers were studied by X-ray diffraction and transmission electron microscopy (TEM). The in-plane epitaxial relationship between the wurtzite ZnO, cubic GGO, and cubic Si follows {10 (1) over bar0}(ZNO)parallel to{4 (22) over bar}(Gd2O3)parallel to{(4) over bar 22}(Si) and the ZnO/GGO interface can be described by the domain matching epitaxy. TEM contrast analysis reveals that the major defect structures in the ZnO films are edge-type threading dislocations and intrinsic basal plane stacking faults. All the ZnO epi-films studied are under a tensile biaxial strain, but no cracks were found. Temperature-dependent photoluminescence results show the excellent optical properties of the obtained ZnO layers, and the origins of the spectral features are discussed.