CHARACTERISTICS OF IN-SITU CL2 ETCHED REGROWN GAAS/GAAS INTERFACES

In situ etch and regrowth experiments on GaAs have been performed. The etching and electrical characteristics of the regrown interface of two different etching methods have been studied. The etching was carried out either by uncracked Cl2 chemical gas etching (CGE) at 300-degrees-C or ion beam assisted etching (IBAE) using Cl2 gas and an argon ion beam. Reflection high-energy electron deflection (RHEED) patterns of IBAE surfaces are streaky indicating that the surfaces are smooth. On the other hand, CGE surfaces exhibit spotty RHEED which is a result of the crystallographic etching nature of CGE at low etching temperatures. The electrical properties of planar p-type etched/regrown samples are studied by deep level transient spectroscopy and capacitance-voltage. CGE samples exhibit a discrete trap level located at 0.52 eV above the valence band maximum (VBM), while IBAE samples display two discrete trap levels at 0.72 and 0.98 eV above VBM.