TRAPPING PHENOMENA IN AVALANCHE PHOTODIODES ON NANOSECOND SCALE

We have developed a novel technique for measuring the release of minority carriers emitted from deep levels in avalanche photodiodes (APD's) at operating conditions. The method, called time-correlated carrier counting (TCCC), is very sensitive and accurate. We have measured densities of filled traps down to 10(9) cm-3 and lifetimes in the nanosecond range. This technique can be useful in tailoring gettering processes for APD's and in studies of traps at high electric fields.