ELECTRON-BEAM-INDUCED MODIFICATION OF GAAS OXIDE FOR INSITU PATTERNING OF GAAS BY CL-2 GAS ETCHING

This in situ patterning process is based on experimental results which show that a photo-oxidized GaAs layer is resistive to Cl2 gas etching, whereas GaAs oxide irradiated by electron beam (EB) can be easily etched. There is an abrupt increase in the etch depth as a function of EB dose. The threshold EB dose for patterning is about 2 x 10(17) electrons/cm2, Which is about three times larger than that of EB-induced Cl2 etching. Auger measurements indicate that GaAs oxide is partially desorbed by EB irradiation. By using this process, the EB system can be separated from the Cl2 gas exposure, so that the system becomes simple and uniform etching can be realized.