GaN growth on Si(111) using simultaneous AlN/α-Si3N4 buffer structure

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.