Study of charge dynamics in high speed power devices using free carrier absorption measurements

A technique is described whereby free-carrier infrared absorption can be used to measure the density of injected electrons and holes within a semiconductor device. Experimental plots of steady state distributions at various current levels, and the open circuit decay of the injected charge distribution are shown for p-i-n rectifier structures both before and after electron irradiation. Anomalous behavior is observed in the open circuit decay of the charge distribution of the electron irradiated device.