GaN Growth on Si(111) Using Simultaneous AlN/α-Si_3N_4 Buffer Structure

摘要

In this study, we examined the growth of a simultaneous AlN/α-Si_3N_4 buffer layer for crack-free GaN growth on a Si(111) substrate. The compressive stress in the AlN/α-Si_3N_4/Si(111) structure retards the cracking in the GaN layer. It is demonstrated that the Al-preseeded layer is a critical factor for accomplishing AlN and the crystalline α-Si_3N_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 α-Si_3N_4 layer on GaN quality were investigated by X-ray diffraction analysis. The 1 : 2 lattice coincidently matches at the α-Si_3N_4(0001)/Si(111) interface, and the 5 : 2 coincident lattice interface at AlN(0001)/α-Si_3N_4(0001) reduces the lattice mismatch in the AlN/α-Si_3N_4/Si(111) structure. The 5 : 4 coincident lattice in the AlN/α-Si_3N_4/Si(111) structure is related to the reduction in the tensile stress in the AlN epilayers. The thickness of crack-free GaN is 2.00 μm. The full widths at half-maximum (FWHM) of the X-ray rocking curve and neutral-donor-bound exciton (D~0X) are 1012arcsec and 5.90meV, respectively.