Selective Area Growth of Cubic GaN on 3C-SiC (001) by Metalorganic Molecular Beam Epitaxy

Abstract

Selective area growth (SAG) of cubic GaN (c-GaN) was performed by metalorganic molecular beam epitaxy (MOMBE). The substrates used in this study were vapor phase epitaxy (VPE)-grown 3C-SiC on Si (001) 4°-off substrates. As a mask, 70-nm-thick SiO2 was formed by thermal oxidation of 3C-SiC and patterned by photolithography or focused ion beam (FIB) etching. GaN was grown on these patterned 3C-SiC substrates without a low-temperature-grown (LT) buffer layer. At a high growth temperature (850°C), growth of GaN did not occur even on a 3C-SiC surface. At a low temperature (800°C), c-GaN was epitaxially grown on a 3C-SiC surface, while polycrystalline GaN (poly-GaN) was grown on the SiO2-masked region. Growth of poly-GaN on the mask was suppressed by optimizing the growth temperature and V/III supply ratio. The possibility of positioning control for c-GaN microcrystals is also presented.