Revisiting the effects of carbon-doping at 10¹⁷ cm⁻³ level on dislocation behavior of Czochralski silicon: from room temperature to elevated temperatures

Carbon is an inevitable impurity subsidiary to oxygen in Czochralski silicon (CZ-Si). Its effects on the properties of CZ-Si have been investigated for decades. However, the research work addressing the dislocation behavior and therefore the mechanical strength of CZ-Si is considerably limited. The previous reports almost focused on the carbon effects on the dislocation behavior of CZ-Si at temperatures not lower than 800 °C. While, how the carbon-doping affects the dislocation behavior of CZ-Si at room temperature or the temperatures below 800 °C has been hardly revealed. In this work, we have comprehensively revisited the effects of carbon-doping at 10¹⁷ cm⁻³ level on the dislocation behavior of CZ-Si from room temperature to elevated temperatures up to 1000 °C. For the first time, we have found that the carbon-doping exerts the exact opposite effects on the dislocation behavior of CZ-Si across a certain temperature (∼ 750 °C). The carbon-doping facilitates the generation of dislocations under the nanoindentation at room temperature and promotes the gliding of microindentation-induced dislocations at temperatures below 750 °C. This is supposed to arise from that the carbon-doping reduces the lattice Peierls energy to a certain extent to resist the dislocation motion. On the contrary, at temperatures from 750 to 1000 °C, the carbon-doping suppresses the gliding of microindentation-induced dislocations, which is due to that the carbon-related complexes or/and oxygen precipitates exhibit the role of dislocation-locking. We believe that the present work gives an insight into the carbon effects on the mechanical strength of CZ-Si.