ION-BEAM ETCHING FOR INSB PHOTOVOLTAIC DETECTOR APPLICATIONS

We first investigate the differences of the InSb mesa etching profiles between ion beam etching and 10:1 lactic:nitric acid chemical etching. The mesa profile obtained by chemical etching always shows the mesa edge trench structure which is due to diffusion limited mechanism. However this effect can be eliminated by ion beam etching. We also present the device characteristics of InSb mesa type photovoltaic detectors which are mesa etched by both techniques. Generation-recombination current, shunt current, and tunneling current are the major components of the reverse currents for both kinds of detectors. However, the detector fabricated on the ion beam etched surface shows lower dark current, which is due to higher shunt resistance, and higher breakdown voltage. These results can be explained by the effects of the different mesa edge profiles.