Growth of silicon- and carbon-doped GaAs by chemical beam epitaxy using H2-diluted DTBSi and CBr4 precursors

Abstract

A wide range of n- and p-type doping levels in GaAs layers grown by chemical beam epitaxy is achieved by using H2-diluted DTBSi and CBr4 as gas precursors for Si and C, respectively. We show that the doping level can be varied by modifying either the concentration or the flux of the diluted precursor. Specifically, we demonstrate carrier concentrations of 7.8×1017–1.4×1019 cm−3 for Si, and 1×1017–3.8×1020 cm−3 for C, as determined by Hall effect measurements. The dependence of Si incorporation on the diluted-precursor flux is found to be linear. In contrast, we observe a superlinear behavior for C doping. The dependence of the electron and hole mobility values on the carrier concentration as well as the analysis of the layers by low-temperature (12 K) photoluminescence spectroscopy indicate that the use of H2 for diluting DTBSi or CBr4 has no effect on the electrical and optical properties of GaAs.