Epitaxial GaAs on SOI Wafers

The feasibility of the heteroepitaxy of high quality GaAs on SOI substrates by the OMCVD process was investigated. The motivation for this is the potential to obtain large area GaAs wafers with improved radiation hardness and, eventually, the monolithic integration of radiation hardened Si and GaAs components. Epitaxial GaAs has been grown on SOI wafers prepared by both isolated silicon epitaxy ISE and high-dose oxygen implantation SIMOX. The use of SIMOX provided an efficient means to obtain SOI wafers with the proper Si surface orientation compatible with a standard GaAs on Si growth technology and an excellent surface morphology was achieved. An optimally oriented ISE surface was apparently not obtained with the resulting surface morphology typical of growth on a singular 100 surface. However, the GaAs grown on ISE shows an improved defect structure while the high quality oxidesilicon interface characteristic of the ISE process is maintained. A n-channel GaAs on SOI FET profile was achieved by doping during the epitaxy process.