Epitaxial Growth of Heterovalent GaAs/Ge and Applications in III-V Monolithic Integration on Si Substrates

Abstract

We review past and present work regarding epitaxial growth of GaAs on Ge surfaces. Early work in molecular beam epitaxy showed that substrate off-cut was a critical factor, although later work with gas-source molecular beam epitaxy and chemical vapor deposition revealed that interface initiation equally controlled GaAs epitaxial layer quality. Using SiGe buffer layers to produce Ge on Si, and GaAs/Ge interfaces with optimal epitaxial control, various minority carrier devices have been fabricated over the past 5 years. To allow the co- habitation of such devices with silicon CMOS in a true monolithic technology, a new substrate platform has been created to allow for the integration of these III-V devices within a Si CMOS fabrication environment.