In situ etching with AsBr3 and regrowth in molecular beam epitaxy

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 substrat es. 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 rough ness for etched samples compared to as-grown structures but no incorporatio n of bromine could be detected. However, an insufficient removal of dopants as well as carbon and oxygen surface contamination was observed in SIMS st udies. A material selectivity between the metallic components In, Ga and Al was in vestigated as well as a crystallographic selectivity in GaAs. Selective etc hing of SiO2 masked GaAs(100) substrates allows in situ preparation of extr emely sharp V-grooves with almost perfectly planar {110} side facets. By MB E regrowth of V-grooves we prepared buried layers and completely embedded w ires which were characterized by SEM and PL.