Browsing by Author "HWANG, HL"

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ANALYSIS OF SEVERAL HIGH-ELECTRON-MOBILITY-TRANSISTOR STRUCTURES BY A SELF-CONSISTENT METHOD
(1991-03-01)
LIU, DG
;
CHIN, TC
;
LEE, CP
;
HWANG, HL
;
電控工程研究所
Three HEMT structures, the single heterostructure HEMT (SH-HEMT), the quantum well HEMT (QW-HEMT) and the delta-doped HEMT (delta-HEMT) were analyzed by solving the Schroedinger equation and Poisson equation self-consistently. The potential and the carrier distributions as well as the charge controlled by gate bias were calculated for different structural parameters. Parallel conduction in AlGaAs, which is severe for SH-HEMTs, is greatly reduced in QW-HEMT and delta-HEMT structures. The effect of layer parameters such as spacer layer thickness and quantum-well width on device performance has been studied. SH-HEMT and QW-HEMT have been fabricated for the confirmation of our analysis.
ENHANCED DIAMAGNETISM IN YBA2CU3O7-DELTA BY HYDROGEN-PLASMA TREATMENT
(1994-09-10)
LEE, MW
;
TAI, MF
;
LEE, HJ
;
HWANG, HL
;
KAO, HCI
We report that the diamagnetism of as-grown YBa2Cu3O7-delta powders can be enhanced by treatment with RF-generated hydrogen plasma. The field-cooling susceptibility at 5 K is found to increase by up to 24%. The enhancement is reproducible for all five samples studied. The lattice parameter c decreases after hydrogenation. For a sample treated for the shortest period, its pinning potential, obtained from magnetic relaxation measurements, is reduced following H-treatment.
EVALUATION OF NI-IN-NI MULTILAYERS FOR THERMALLY STABLE OHMIC CONTACTS TO N-GAAS
(1995-09-01)
HSIA, ST
;
LEE, CP
;
HWANG, HL
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A thermally stable, low resistance ohmic contact system Ni-Ln-Ni to n-GaAs was investigated. The lowest value of the specific contact resistance rho(c) was 1.71 x 10(-4) Omega cm(2). Hearing the contact up to 400 degrees C for 5 h did not obviously change the value of rho(c). It was observed by Auger electron spectroscopy and X-ray diffraction that Ni-Ln compounds, Ga-Ni and InAs formed at the metal-GaAs interface. It was noted that In reacted with GaAs and formed a heterojunction ohmic contact (such as InAs-InxGa1-xAs-GaAs) and due to the low melting point (156 degrees C) of In, additions of Ni are needed to completely react the remaining In to form a high melting point compound.
EVALUATION OF NI-IN-NI MULTILAYERS FOR THERMALLY STABLE OHMIC CONTACTS TO N-GAAS
(1995-09-01)
HSIA, ST
;
LEE, CP
;
HWANG, HL
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
A thermally stable, low resistance ohmic contact system Ni-Ln-Ni to n-GaAs was investigated. The lowest value of the specific contact resistance rho(c) was 1.71 x 10(-4) Omega cm(2). Hearing the contact up to 400 degrees C for 5 h did not obviously change the value of rho(c). It was observed by Auger electron spectroscopy and X-ray diffraction that Ni-Ln compounds, Ga-Ni and InAs formed at the metal-GaAs interface. It was noted that In reacted with GaAs and formed a heterojunction ohmic contact (such as InAs-InxGa1-xAs-GaAs) and due to the low melting point (156 degrees C) of In, additions of Ni are needed to completely react the remaining In to form a high melting point compound.
VERY-LOW TEMPERATURE DEPOSITION OF POLYCRYSTALLINE SI FILMS FABRICATED BY HYDROGEN DILUTION WITH ELECTRON-CYCLOTRON-RESONANCE CHEMICAL-VAPOR-DEPOSITION
(1995-02-01)
WANG, KC
;
CHENG, KL
;
JIANG, YL
;
YEW, TR
;
HWANG, HL
Characteristics of polycrystalline silicon films deposited both on SiO2 and Coming 7059 glass substrates are presented in this paper. The silicon films were deposited by a hydrogen dilution method using electron cyclotron resonance chemical vapor deposition at 250 degrees C without any thermal or laser annealing. The hydrogen dilution ratio was between 90% and 99%. The geometric configuration and surface morphology of polycrystalline silicon films were studied by atomic force microscopy. The largest grain size of the deposited silicon films; identified by plan-view transmission electron microscopy dark-field imaging, was about 1 mu m. From Raman spectrum, the crystalline fraction of polycrystalline silicon films was identified to be nearly 100%. The polycrystalline silicon was found to be preferentially [111]- and [110]-oriented, from the X-ray diffraction pattern.