Small signal Surface Photo-voltage (SPV) measurement techniques have been applied to monitor ion implants typical of those used for layer-transfer SOI processes. This SPV wafer mapping technique was investigated for sensitivity to dose, implant uniformity, and repeatability for hydrogen and helium implants into (100) silicon wafers through a 1450Aå surface oxide. A normalized sensitivity of approximately 1.2 for the investigated cases was observed. A demonstrated repeatability of less than 0.5% 1-sigma standard deviation was measured for a multi-day period on hydrogen implanted wafers. The small signal SPV metrology technique presented allows in-line SPC control of the critical ion implant step within the SOI wafer manufacturing process.
