Sb-mediated growth of n- and p-type AlGaAs by molecular beam epitaxy

Abstract

The Sb-mediated growth of Al0.65Ga0.35As is studied for Sb/III flux ratios from 0% to 2% and growth temperatures from 580 to 720 °C. The surface morphology and electrical properties are found to strongly depend on both the growth temperature and Sb flux. As an isoelectronic dopant, Sb improves the conductivity of n-Al0.65Ga0.35As and reduces the conductivity of p-Al0.65Ga0.35As. As a surfactant, Sb improves the surface morphology of Al0.65Ga0.35As at all growth temperatures with the most dramatic improvement occurring at 670 °C. The smoothest surface (0.2 nm root-mean-square roughness height) was obtained at 700 °C using a Sb/III flux ratio of 0.02. This work demonstrates that Sb-mediated molecular beam epitaxy growth of n-AlGaAs effectively eliminates the “forbidden temperature gap” for device quality n-AlGaAs.