Selective liquid phase epitaxy and defect reduction in GaAs grown on GaAs-coated silicon by molecular beam epitaxy

This letter reports the first successful liquid phase epitaxial (LPE) growth of GaAs on GaAs-coated Si grown by molecular beam epitaxy (MBE). The LPE growth was found to be strongly dependent on the width of the oxide stripe window which defined the area of the sample that was accessible to the LPE melt. Uniform single-crystal layers of GaAs were obtained when the stripe was narrower than 20 μm; in contrast, meltback of the GaAs layers was observed in larger stripes. The minimum dislocation density of the LPE layer that was determined from cross-sectional transmission electron microscopy was about 2–5×106 cm−2. This value was about two orders of magnitude lower than the dislocation density that was observed in the MBE GaAs-on-Si layer which served as a substrate for the LPE growth.