The effect of gas phase growth parameters on the composition of InGaAs in the hydride VPE process

A 1.4-μm thick InGaAs layer exhibiting an x-ray diffraction linewidth of 18 arcs has been grown on an InP substrate. This is the best crystalline perfection ever reported for InGaAs, as far as the author is aware. The effect of gas composition on lattice mismatch has been investigated for InGaAs layers grown under a variety of conditions. An empirical equation has been developed which relates lattice mismatch(Δa/a) to metals ratio, mole fraction of AsH₃ and mole fraction of HC1. Values of(Δa/a) calculated using this equation are in good agreement with experiment. The metals ratio for lattice match is shown to vary linearly with the growth rate. This observation is shown to be consistent with mass transfer limitation in the gas phase. As a further consequence, relationships between layer thickness uniformity and lattice mismatch uniformity and between growth rate and gas composition are derived.