Selective Epitaxial Growth of GaAs on Ge Substrates with a SiO2 Pattern

摘要

We have selectively grown thin epitaxial GaAs films on Ge substrates with theaid of a 200 nm thin SiO2 mask layer. The selectively grown structures havelateral sizes ranging from 1 um width up to large areas of 1 by 1 mm2. Thegrowth is fully selective, thanks to an optimized growth procedure, consistingof a 13 nm thin nucleation layer grown at high pressure, followed by lowpressure growth of GaAs. This growth procedure inhibits the nucleation of GaAson the mask area and is a good compromise between reduction of loading effectsand inhibition of anti phase domain growth in the GaAs. Nevertheless, bothmicroscopic and macroscopic loading effects can still be observed on x-sectionSEM images and profilometer measurements. X-ray diffraction and low temperaturephotoluminescence measurements demonstrate the good microscopic characteristicsof the selectively grown GaAs.