Area selective epitaxy of InAs on GaAs(0 0 1) and GaAs(1 1 1)A by migration enhanced epitaxy

Abstract

Area selective epitaxy of InAs on semi-insulating GaAs(001) and GaAs(111)A substrates masked by SiO2 has been investigated by using migration enhanced epitaxy (MEE). Successful area selective epitaxy has been achieved in an optimized substrate temperature range 460°C<TS<500°C. Scanning electron microscopy and atomic force microscopy measurements indicated a competing behavior between an etching and a growth process in dependence of the substrate temperature and the annealing time ta after In deposition in the MEE sequence. The etching process is most likely connected to Ga dangling bonds along the {n11}A plane. Deposited In atoms react with Ga atoms in the open window area and are re-evaporated and/or incorporated into the InAs islands. In case of InAs growth on GaAs(001) no profound difference was found between structures grown by the MEE sequence and structures grown by simultaneous deposition of In and As. In contrast, for InAs/GaAs(111)A the growth mode changes drastically with the applied growth method.