Growth and etching characteristics of (001) β-Ga2O3 by plasma-assisted molecular beam epitaxy

We investigated the homoepitaxial growth and etching characteristics of (001) ?-Ga2O3 by plasma-assisted molecular beam epitaxy. The growth rate of ?-Ga2O3 increased with increasing Ga-flux, reaching a clear plateau of 56 nm h?1, and then decreased at higher Ga-flux. The growth rate decreased from 56 to 42 nm h?1 when the substrate temperature was increased from 750 ?C to 800 ?C. The growth rate was negative (net etching) when only Ga-flux was supplied. The etching rate proportionally increased with increasing the Ga-flux, reaching 84 nm h?1. The etching was enhanced at higher temperatures. It was found that Ga-etching of (001) ?-Ga2O3 substrates prior to the homoepitaxial growth markedly improved the surface roughness of the film.