Browsing by Author "Ku, Jui Tai"

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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.