Photoelectric C-V profiling of majority charge carriers and effective lifetimes of minority charge carriers in gettered GaAs wafers

The procedure for photoelectrochemical C-V profiling of the concentration of majority charge carriers and effective lifetimes of minority charge carriers in high-resistivity thick (1.6 mm) GaAs wafers subsequently to their gettering is described. Gettering was performed by both one-side and two-side coating of the wafers with a Y film and subsequent thermal treatment at 700 and 800°C. It was demonstrated that the concentration profile N _d-N _a and the effective lifetime for minority charge carriers throughout the wafer are rather uniform in both cases. This procedure makes it possible to measure the charge carrier concentration as low as 10¹² cm^?3.