GaN Growth on Si(111) Using Simultaneous AlN/$\alpha$-Si3N4 Buffer Structure

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In this study, we examined the growth of a simultaneous AlN/$\alpha$-Si3N4 buffer layer for crack-free GaN growth on a Si(111) substrate. The compressive stress in the AlN/$\alpha$-Si3N4/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 $\alpha$-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 on 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 AlN/$\alpha$-Si3N4/Si(111) structure. The $5:4$ coincident lattice in the AlN/$\alpha$-Si3N4/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 (D0X) are 1012 arcsec and 5.90 meV, respectively.
2008-07-25