Indium desorption from strained InGaAs/GaAs quantum wells grown by molecular beam epitaxy

Abstract

The desorption and segregation of indium during molecular beam epitaxy growth of strained InGaAs/GaAs multiple quantum wells have been investigated by secondary ion mass spectroscopy (SIMS). The quantum wells were grown at various substrate temperatures, and the growths were interrupted at specified interfaces. Results indicate that indium desorption and segregation increase as the growth temperature is increased regardless of the type of growth interruption. However, the desorption was relatively high in the case of wells whose growths were interrupted at the top of the wells compared to the cases of bottom and no interruption, probably due to longer annealing of the exposed well surfaces at a high temperature. Similar results were obtained for the indium segregation. In all the cases, appreciable desorption starts only above 550 °C. SIMS results were analyzed using a simple rate-equation model for indium desorption, and the activation energy for indium desorption was found to be constant for both the top and bottom interrupted samples.