Recognition and recombination strength evaluation by LBIC of dislocations in FZ and Cz silicon wafers

摘要

In the present work, dislocation networks are investigated in Czochralski (Cz) and in float zone (FZ) grown silicon wafers by the Light Beam Induced Current (LBIC) mapping technique at different wavelengths, which appears to be able to recognize and to detect these networks and to evaluate their recombination strength. Dislocations are found to be more recombining in Cz than in FZ. It is shown that in Cz wafers, a four hours phosphorus diffusion at 900℃, realized before dislocations creation, impedes the formation of oxygen precipitates during subsequent annealings. In FZ dislocated wafers, a phosphorus diffusion at 850℃ for 30 min cancels the LBIC contrast of dislocations. Electrical activity of these defects which are still physically present as shown by X-Ray topography, seems to disappear.