On the aging of avalanche light emission from silicon junctions

The evolution of photon emission from the emitter-base junctions of bipolar transistors during electrical aging is monitored for the first time. Both electrical and optical characteristics are analyzed, Local variations of li ght emission intensity are observed for junctions biased at avalanche break down. During aging, regions of emission coalesce into small, bright regions ; the total emission for the entire junction remains stable and relatively high. Changes in transistor current gain and breakdown voltage correlate wi th changes in light emission, and are consistent with a hydrogen migration model.