Growth limitations by the miscibility gap in liquid phase epitaxy of Ga1−xInxAsySb1−y on GaSb

Abstract

The boundary line (binodal curve) of the solid phase miscibility gap of the Ga1−xInxAsySb1−y quaternary alloy has been calculated from the regular solution model, taking into account the latticemismatched strain energy induced by a GaSb substrate. A calculation suggests that the miscibility gap is reduced and epitaxial layers might be deposited over the entire range of lattice-matched compositions at 615°C. Ga1−xInxAsySb1−y epitaxial layers have been grown by liquid phase epitaxy on (100)- and (111)B- oriented GaSb substrates. The lattice-matched epitaxial layers which were richest in indium (x = 0.23) for the (100) orientation and x = 0.26 for the (111)B orientation have compositions located in the vicinity of the boundary of the miscibility gap calculated ignoring the strain energy, showing that stabilization by the substrate is far less effective than predicted.