We have investigated the motion of dislocations originating from Vicker indentations in single-crystalline silicon wafers subjected to high temperature rapid thermal processing (RTP) under different ambients. It is found that the dislocations move very rapidly due to the release of residual stress around the indentations during the RTP. Moreover, as the RTP temperature exceeds 1100 °C, the dislocation gliding distances in the specimens subjected to the RTP in N2 atmosphere are much shorter than in Ar ambient. We believe that the nitrogen atoms injected into the indentation by the RTP under N2 ambient exhibit a pinning effect on dislocation motion. It is thus shown that the high temperature RTP in N2 ambient can improve the mechanical strength of silicon wafer.