Browsing by Author "Chi-Lang Nguyen"

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Characterizations of GaN Films Grown on Si (111) Substrates with Various Growth Temperatures of Multiple AlN Buffer Layers
(2012)
Binh-Tinh Tran
;
Chang, Edward Yi
;
Lin, Kung-Liang
;
Luong, Tien-Tung
;
Yu, Hung-Wei
We present the effect of multiple AlN buffer layers on characterizations of GaN film quality, which includes a thin high-low-high-temperature (HLHT) AlN buffer layers. The study is based on two different thicknesses of the GaN films on the buffers and found that the HLHT AlN buffer layers could significantly affect on the GaN films qualities. The buffer plays a very important role for the growth of GaN film on Si (111) substrate. The GaN film with an uniformly faceted surface and very high-quality has been obtained at the optimized multiple HLHT AlN buffer layers of 50-nm-thick at 1010-800-1010 degrees C.
Effect of Low Temperature Ge Seed Layer and Post Thermal Annealing on Quality of Ge1-xSix (0.05 <= x <= 0.1) Graded Buffer Layers by UHV-CVD
(2014-07-01)
Chi-Lang Nguyen
;
Nguyen Hong Quan
;
Binh-Tinh Tran
;
Su, Yung-Hsuan
;
Tang, Shih-Hsuan
High crystal quality, smooth surface and fully relaxed Ge1-xSix (0.05 <= x <= 0.1) buffers are grown on 6 degrees-off (100) Si substrate by UHV-CVD. A low-temperature (LT) Ge seed layer is used to improve the quality of the Ge1-xSix buffers. In this study, the LT-Ge seed layer is deposited directly onto the Si substrate at a low temperature of 315 degrees C. After that, stress-free Si0.1Ge0.9 and Si0.05Ge0.95 layers are grown, respectively. An in-situ annealing process is also performed for the Si0.1Ge0.9/LT-Ge layers to increase the degree of relaxation. The total thickness of the epitaxial layer is 270 nm, with the average surface roughness at 0.6 nm.
Effect of Multiple AlN Layers on Quality of GaN Films Grown on Si Substrates
(2014-11-01)
Binh Tinh Tran
;
Lin, Kung-Liang
;
Sahoo, Kartika Chandra
;
Chung, Chen-Chen
;
Chi-Lang Nguyen
In this paper, we present the effect of multiple thin high-low-high-temperature AlN (HLHT AlN) nucleation layers on GaN film quality. A 1.9-mu m-thick GaN film gown on Si (111) substrate shows that the multiple HLHT AlN nucleation layers have a significant effect on GaN film quality. This process also plays a very important role in the growth of GaN films on Si (111) substrates. A high quality GaN film with a uniformly faceted surface with very low dislocation densities is obtained at the optimized multiple HLHT AlN nucleation layers 50-nm thick at a temperature of 1010-800-1010 degrees C and a growth pressure of 50 Torr.
Influence of post deposition annealing temperatures on electrical properties of Al2O3/InSb MOSCAPs
(2012-01-01)
Hai-Dang Trinh
;
Lin, Yue-Chin
;
Chang, Edward Yi
;
Hong-Quan Nguyen
;
Wang, Shin-Yuan
The influence of post deposition annealing (PDA) temperatures on electrical characteristics of Al2O3/InSb metal-oxide-semiconductor capacitor (MOSCAP) structures is investigated. Low frequency C-V responses with strong inversion behavior in the whole range of measured frequency (100 Hz-1 MHz) are observed, indicating very short minority carrier response time in InSb. The PDA temperature of 300 degrees C and above would result in the reduction of maximum capacitance. At the PDA temperature of above 300 degrees C the C-V hysteresis, frequency dispersion and stretch out increases significantly, indicating the degradation of the MOSCAP structures. The degradation might relate to the interdiffusion between Al2O3 and InSb during thermal steps.