Vapor phase diffusion and surface diffusion combined model for InGaAsP selective area metal–organic vapor phase epitaxy

The growth rate profiles adjacent to selective area masks were studied for InP, InGaAs and InGaAsP by metal–organic vapor phase epitaxy. Time-proportional growth rate increments were found for InP growth at the mask edge. The growth rate of InP at the edge saturated after the length of (1 1 1)B plane became larger than 1.4 μm, which corresponds to the migration length of an In precursor on this plane. The time evolution of the InP layer at the mask edge was modeled as (1) precursors stuck on (1 1 1)B plane migrate to (1 0 0) plane and (2) they diffuse on that plane as well as get incorporated there. The simulated thickness of InP layers at the mask edge showed excellent agreement with experimental data. In the case of InGaAs and InGaAsP, there were no indications of surface diffusion in the thickness profile. However, the distribution of the photoluminescence wavelength of InGaAsP layers suggested that the surface diffusion of Ga precursor on the (1 0 0) plane of the InGaAsP layer existed with the diffusion length of as long as 8 μm.