INCREASED THERMAL GENERATION RATE IN GAAS DUE TO ELECTRON-BEAM METALLIZATION

Leakage currents due to thermal generation in a reverse-biased p-n junction can be accurately monitored by measuring the capacitance recovery transient of a p-n-p structure. Using this technique, it has been demonstrated that the thermal generation in the bulk depletion region of GaAs p-n junctions grown by molecular beam epitaxy can be as much as three orders of magnitude greater for samples metallized in electron-beam evaporators as compared to thermal evaporators. The increase in thermal generation rate is shown to be dependent upon the device area exposed during the evaporation, the type of metal initially evaporated onto the sample, the growth conditions during molecular beam epitaxy, and the depth of the p-n junction from the semiconductor surface.