Browsing by Author "Yang, Tsung Hsi"

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GaN growth on Si(111) using simultaneous AlN/alpha-Si(3)N(4) buffer structure
(2008-07-01)
Chang, Jet Rung
;
Yang, Tsung Hsi
;
Ku, Jui Tai
;
Shen, Shih Guo
;
Chen, Yi Cheng
In this study, we examined the growth of a simultaneous AIN/alpha-Si(3)N(4) buffer layer for crack-free GaN growth oil a Si(111) substrate. The compressive stress in the AlN/alpha-Si(3)N(4)/Si(111) structure retards the cracking ill the GaN layer. It is demonstrated that the Al-preseeded layer is a critical factor for accornplishing AlN and the crystalline alpha-Si(3)N(4) layer simultaneously. The effect of Al layer deposition time on the c-axis lattice constants of the subsequent AlN layer, and the effect of the crystalline alpha-Si(3)N(4) layer oil GaN quality were investigated by X-ray diffraction analysis. The 1 : 2 lattice coincidently matches at the alpha-Si(3)N(4)(0001)/Si(111) interface, and the 5 : 2 coincident lattice interface at AlN(0001)/alpha-Si(3)N(4)(0001) reduces the lattice mismatch in the AIN/alpha Si(3)N(4)/Si(111) structure. The 5 : 4 coincident lattice in the AIN/alpha-Si(3)N(4)/Si(111) structure is related to the reduction in the tensile stress in the AIN epilayers. The thickness of crack-free GaN is 2.00 mu m. The full widths at half-maximum (FWHM) of the X-ray rocking curve and neutral-donor-bound exciton (D degrees X) are 1012arcsec and 5.90meV, respectively.
GaN growth on Si(111) using simultaneous AlN/alpha-Si3N4 buffer structure
(2008-07-01)
Chang, Jet Rung
;
Yang, Tsung Hsi
;
Ku, Jui Tai
;
Shen, Shih Guo
;
Chen, Yi Cheng
In this study, we examined the growth of a simultaneous AIN/alpha-Si3N4 buffer layer for crack-free GaN growth oil a Si(111) substrate. The compressive stress in the AlN/alpha-Si3N4/Si(111) structure retards the cracking ill the GaN layer. It is demonstrated that the Al-preseeded layer is a critical factor for accornplishing AlN and the crystalline alpha-Si3N4 layer simultaneously. The effect of Al layer deposition time on the c-axis lattice constants of the subsequent AlN layer, and the effect of the crystalline alpha-Si3N4 layer oil GaN quality were investigated by X-ray diffraction analysis. The 1 : 2 lattice coincidently matches at the alpha-Si3N4(0001)/Si(111) interface, and the 5 : 2 coincident lattice interface at AlN(0001)/alpha-Si3N4(0001) reduces the lattice mismatch in the AIN/alpha Si3N4/Si(111) structure. The 5 : 4 coincident lattice in the AIN/alpha-Si3N4/Si(111) structure is related to the reduction in the tensile stress in the AIN epilayers. The thickness of crack-free GaN is 2.00 mu m. The full widths at half-maximum (FWHM) of the X-ray rocking curve and neutral-donor-bound exciton (D degrees X) are 1012arcsec and 5.90meV, respectively.
Growth of free-standing GaN layer on Si(111) substrate
(2009-03-15)
Yang, Tsung Hsi
;
Ku, Jui Tai
;
Chang, Jet-Rung
;
Shen, Shih-Guo
;
Chen, Yi-Cheng
This investigation demonstrates the epitaxial growth of a free-standing GaN layer on Si(1 1 1) using a funnel-like GaN nano-rod buffer structure. The funnel-like GaN nano-rods were directly grown on Si substrates by RF-plasma molecular beam epitaxy. Free-standing GaN layers were achieved through the coalescence of funnel-like GaN nano-rods by the metalorganic chemical vapor deposition. This study examines the structure, optical characteristics and stress of GaN nano-rods and free-standing GaN layers. The c-axis lattice constant of the strain-free Ga-face GaN layer on Si is 5.1844 angstrom, as determined by high-resolution X-ray diffraction. The fully relaxed band edge at 3.468 eV without deep-level emission around 2.3 eV, was revealed in a free-standing GaN layer on Si, using photoluminescence. (C) 2008 Elsevier B.V. All rights reserved.
Growth of GaAs epitaixial layers on Si substrate by using a novel GeSi buffer layer
(2005-02-03)
Chang, Edward Y.
;
Luo, Guangli
;
Yang, Tsung Hsi
;
Chang, Chung Yen
This invention provides a process for growing Ge epitaixial layers on Si substrate by using ultra-high vacuum chemical vapor deposition (UHVCVD), and subsequently growing a GaAs layer on Ge film of the surface of said Ge epitaixial layers by using metal organic chemical vapor deposition (MOCVD). The process comprises steps of, firstly, pre-cleaning a silicon wafer in a standard cleaning procedure, dipping it with HF solution and prebaking to remove its native oxide layer. Then, growing a high Ge-composition epitaixial layer, such as Si0.1Ge0.9 in a thickness of 0.8 μm on said Si substrate by using ultra-high vacuum chemical vapor deposition under certain conditions. Thus, many dislocations are generated and located near the interface and in the low of part of Si0.1Ge0.9 due to the large mismatch between this layer and Si substrate. Furthermore, a subsequent 0.8 μm Si0.05Ge0.95 layer, and/or optionally a further 0.8 μm Si0.02Ge0.98 layer, are grown. They form strained interfaces of said layers can bend and terminate the propagated upward dislocation very effectively. Therefore, a film of pure Ge is grown on the surface of said epitaixial layers. Finally, a GaAs epitaixial layer is grown on said Ge film by using MOCVD.
Light emitting device and fabrication method therefor
(2009-11-12)
Chang, Chun-Yen
;
Yang, Tsung Hsi
A light emitting device (LED) structure formed on a Group IV-based semiconductor substrate is provided. The LED structure includes a Group IV-based substrate, an AlN nucleation layer formed on the Group IV-based substrate, a GaN epitaxial layer formed on the AlN nucleation layer, a distributed Bragg reflector (DBR) multi-layer structure formed on the epitaxial layer, and an LED active layer formed on the DBR multi-layer structure.