Selective growth and associated faceting and lateral overgrowth of GaAs on a nanoscale limited area bounded by a SiO2 mask in molecular beam epitaxy

We report homoepitaxial selective growth of GaAs on a 350 nm period two-dimensional SiO2-patterned substrate by molecular beam epitaxy. Ga atoms are largely desorbed from a SiO2 surface at high growth temperature (≳615 °C) when the Ga flux is about 0.1 monolayer/s. Under these conditions, a GaAs epilayer selectively grown in circular openings on GaAs(100) with a diameter of about 120–200 nm bounded by a 40 nm thick SiO2 mask shows faceting over its entire surface for 100 nm thick deposition. Lateral growth associated with faceting over the SiO2 mask in 〈100〉 is observed.