A GaAs defect-free epitaxial layer was grown onto Si via a Ge concentration graded SiGe on insulator (SGOI) for application in high channel-mobility metal-oxide-semiconductor field effect transistor. The SGOI layer, 42nm-thick, served as a compliant and intermediate buffer to reduce the lattice and thermal expansion mismatches between Si and GaAs. A modified two-step Ge condensation technique achieved a surface Ge concentration in SGOI which was as high as 71%. It was also found that low-temperature migration enhanced epitaxy during the initial GaAs nucleation on the SGOI surface was critical to the obtention of device-quality GaAs layer by epitaxial growth.

Integration of GaAs Epitaxial Layer to Si-Based Substrate using Ge Condensation and Low-Temperature Migration Enhanced Epitaxy Techniques. H.J.Oh, K.J.Choi, W.Y.Loh, T.Htoo, S.J.Chua, B.J.Cho: Journal of Applied Physics, 2007, 102[5], 054306