Oxygen precipitate precursors and size thresholds for the preferential nucleation for copper and nickel precipitation in silicon: the detection of copper and nickel contamination by minority carrier lifetime methods

The precipitation of Cu and Ni at very small oxygen clusters has been investigated by an Elymat-based photocurrent technique. The technique has been demonstrated to be capable of revealing the point at which the precipitation at oxygen cluster sites becomes predominant over surface precipitation, even for very small amounts of metal contaminants. This corresponds to the threshold for effective gettering. Conversely the technique may also be useful as a simple and convenient method for detecting small amounts of Cu or Ni contamination by electrical means.