ABSTRACT
A new photoscanning method for the detection of doping inhomogeneities in semiconductors is described were contacts or current leads at the sample are avoided, thus making it possible to evaluate the doping variations of semiconductor wafers completely nondestructively. Photoinduced currents are generated by laser light focused on the wafer surface and scanned over it. These currents are detected by an extremely sensitive dc SQUID (dc Superconducting QUantum Interference Device).
