Effect of growth parameters on composition of InGaAs in hydride VPE.

A 1.4micron thick InGaAs layer exhibiting an x-ray diffraction linewidth of 18 arc s has been grown on an InP substrate. This is the narrowest linewidth 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 (DELTA a/a) to metals ratio, mole fraction of AsH sub 3 and mole fraction of HCl. Values of (DELTA a/a) calculated using this equation are in good agreement with experiment. Metals ratio for lattice match is shown to vary linearly with growth rate. This observation is shown to be consistent with gas phase diffusion control of the deposition process. As a further consequence, relationships between layer thickness uniformity and lattice mismatch uniformity and between growth rate and gas composition are derived.