CHARACTERIZATION OF IN-SITU CL-2-ETCHED GAAS BUFFER LAYERS AND REGROWN GAAS/ALGAAS QUANTUM-WELLS

We studied the interface between an in situ Cl-2-gas-etched GaAs buffer layer and a regrown AlGaAs layer, as a function of the etching temperature, together with the optical properties of etched buffer layers and GaAs/AlGaAs quantum wells (QWs) which were regrown on the buffer layers. In the case of etching at 70 degrees C, degradation of the photoluminescence (PL) was observed for the etched GaAs buffer layer and the regrown QWs, which extended 100 nm from the interface. With increasing etching temperature up to 200 degrees C, on the other hand, the PL was greatly improved for both the etched GaAs buffer layer and the regrown QWs This was due to the reduced C and O impurity accumulation at the etched/regrown interface, which was confirmed by secondary ion mass spectroscopy measurements.