Molecular beam epitaxial growth of (Al,Ga)As/GaAs heterostructures and Si doping characterization study on vicinal (110) GaAs substrates

Abstract

The growth of device quality (Al,Ga)As/GaAs heterostructures on [110]-oriented GaAs substrates is reported. In-situ reflection high energy electron diffration (RHEED) oscillation and ex-situ photoluminescence measurements are used to optimize the growth conditions. Si-doped GaAs epi-layers with different dopant concentrations grown at various substrate temperatures and differing As 4⧸Ga flux ratios were characterized by room temperature Hall effect measurements. It is found that silicon, as a dopant, can behave amphoterically in [110]-oriented GaAs epi-layers. By appropriately adjusting either the substrate temperature or the As 4⧸Ga flux ratio, it is possible to grow high quality n-type or p-type material using only silicon as a dopant. Up to a transition temperature of about 630°C, silicon atoms can be incorporated as donor impurities for an As 4⧸Ga flux ratio of 5. At and above this temperature, the atoms occupy lattice sites where they behave as acceptors for the same flux ratio.