An imaging system for detecting recombination center defects in a semiconductor wafer in which an oxidized wafer is pre-treated by charging the oxide in a corona discharge and then passing the charged wafer below a stationary bifurcated electrode. A focused laser beam is scanned between the arms of the bifurcated electrode and along its length as the wafer is slowly moved transversely to the direction of laser scanning. The signal from the bifurcated electrode is displayed in an imaging system, one axis of which is synchronized to the laser scanning and the other axis is synchronized to the movement of the wafer.
展开▼
