Strain control of GaN grown on 3C-SiC/Si substrate using AlGaN buffer layer



GaN layers were grown on 3C-SiC/Si substrates with AlGaN intermediate layers with various thickness and AlN mole fraction by low-pressure metal-organic vapor phase epitaxy (LP-MOVPE). The effects of the interlayer on the crystal quality and strain-status of GaN epilayer were investigated systematically by varing the thickness and the Al mole fraction of the AlGaN. Raman scattering and X-ray diffraction results show that the AlGaN with thinner thickness and higher Al mole fractions can improve the crystalline quality of the GaN epilayer and the redue the strain at the same time. This phenomenon should be attributed to three dimensional (3D) growth at the initial stage of (the) GaN epitaxy. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)