Abstract: The present method allows detection of heavy metal impurities introduced into a silicon wafer during an ion implantation procedure. The method is quick, non-destructive, and functions in the presence of extensive lattice damage created during ion implantation. A thermal treatment follows ion implantation to cause any heavy metal impurities to diffuse into near-surface regions adjacent to major surfaces. A major surface of the silicon wafer is subjected to a high-injection SPV frequency sweep procedure before and after the thermal treatment. During each high-injection SPV frequency sweep procedure, the major surface is subjected to a train of light pulses modulated at frequencies within a frequency range of interest spanning from a low frequency cutoff (about 280 Hz) to a high frequency cutoff (about 10 kHz). Surface charge values are derived from surface photovoltages measured at each modulation frequency.