In situ etching with AsBr3 and regrowth in molecular beam epitaxy

Abstract

We report in situ etching in III-V molecular beam epitaxy (MBE) with AsBr3 as the etching species and MBE regrowth of in situ structured GaAs substrates. The application of AsBr3 provides atomic layer precise etching as well as full compatibility with MBE growth. The quality of etched interfaces in GaAs/AlGaAs heterostructures is investigated by photoluminescence (PL) and Hall-effect measurements. They indicate a slightly enhanced interface roughness for etched samples compared to as-grown structures but no incorporation of bromine could be detected. However, an insufficient removal of dopants as well as carbon and oxygen surface contamination was observed in SIMS studies. A material selectivity between the metallic components In, Ga and Al was investigated as well as a crystallographic selectivity in GaAs. Selective etching of SiO2 masked GaAs(100) substrates allows in situ preparation of extremely sharp V-grooves with almost perfectly planar {110} side facets. By MBE regrowth of V-grooves we prepared buried layers and completely embedded wires which were characterized by SEM and PL.