Hetero-Epitaxy of III-V Compounds by MOCVD on Silicon Substrates

Abstract

Over the past few years, we have successfully developed heteroepitaxial techniques to grow device quality III-V and III-nitride structures on silicon substrates by MOCVD. We have demonstrated very good device performance with conventional III-V HEMT (High Electron Mobility Transistor) structures grown and fabricated on Si substrates. These devices were nearly latticematched to InP. Unlike previous approaches of using a Ge buffer, compositional grading, or superlattices, we adopted similar techniques that have been well developed for hetero-epitaxy of III-nitrides on sapphire substrates. A well-tuned nucleation layer deposited at low-temperature followed by regular high-temperature epitaxy is effective in producing good quality layers for device applications. Aided by in-situ photoreflectance anisotropy and other material characterization tools, device quality epi-layers can be grown and very good transistor characteristics were measured.