Incorporation of indium and gallium in atomic layer epitaxy of InGaAs on InP substrates

The incorporation of indium (In) and gallium (Ga) group III elements in the growth of ternary InGaAs layers by atomic layer epitaxy (ALE) was investigated using various growth conditions. By dividing the growth rate of InGaAs into InAs and GaAs components, it was found that the incorporation of In and Ga strongly depends on the source exposure time, H2 purge, and growth temperature. At 500 °C the growth rate of InAs is determined by the metalorganic precursor supply duration and the growth rate of GaAs is determined by the AsH3 exposure duration. With increasing H2 purge time, Ga incorporation is enhanced. At an elevated temperature of 550 °C the incorporation of both In and Ga is dependent on metalorganic precursor exposure, while at a low temperature of 400 °C the In and Ga incorporation is limited by the AsH3 exposure. A growth model was proposed to explain the ALE growth of a ternary InGaAs layer at 500 °C, which may involve metal In and GaCH3 adsorbates as the In and Ga species on the growing surface, respectively.