Radiation-induced defect introduction rates in semiconductors

The defect introduction rate at 295 K by 1-MeV electrons in the p-side of n/sup +/-p silicon junctions under various applied voltages was measured using both DLTS and C-V techniques. The introduction rate of most defects is a strong function of applied bias and distance from the junction. Open circuit irradiation produces the smallest introduction rate while reverse bias enhances the rate by a factor of five for most defects. The C-V technique finds three times the concentration of defects that the DLTS technique finds. The C-V technique cannot distinguish types of defects: it sums all defects. Heavy reverse bias irradiations produced unstable junctions that could be partially restabilized by further open circuit irradiations. The electron-hole pairs generated by the irradiation appear to play a major role in the development of the final defect population resulting from the same irradiation. Even in a short irradiation, defects initially created early in the irradiation are altered or annealed by continued irradiation Recombination-enhanced diffusion theory appears to explain some of the results and, therefore, may be an important factor in the defect introduction process in many semiconductors.<
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