Growth of GaxIn1−xAs by low-pressure metalorganic vapor-phase epitaxy

Abstract

Ga_xIn_1−xAs layers have been grown on GaAs by low‐pressure metalorganic vapor‐phase epitaxy using trimethylgallium, trimethylindium, and arsine. The effects of varying the substrate temperature and gas composition on the growth rate and layer composition have been studied. It is found that very uniform ternary layers containing up to more than 20% In can be routinely grown over areas of ∼2×2 cm². Stable growth is achieved at all indium concentrations, at various substrate temperatures, and gas flow rates. The growth rate and the layer composition are controlled by the organometallic‐compound partial pressures in the reactor. The samples have a mirrorlike surface which shows a uniform crosshatched pattern under an optical microscope, typical of lattice mismatched epitaxial layers. The residual concentration is low (n≲6×10¹⁴ cm⁻⁴) but the low‐temperature mobility decreases with increasing indium content in the layers. This mobility reduction is accompanied by a change in the photoluminescence spectra. At large indium concentrations, the spectra are dominated by a narrow line at 50–70 meV below the excitonic emission.