Effect of ramping on oxygen precipitates and Cu–vacancy complex in Czochralski silicon

•Oxygen precipitates and Cu–vacancy complex in Cz-silicon were investigated.•A lower start ramping temperature led to more oxygen precipitates.•A higher Cu contamination temperature led to more oxygen precipitates.•A lower start ramping temperature could reduce the Cu–vacancy complex.•Cu–vacancy complex decreased with the increase of Cu contamination temperature.

The effect of ramping on oxygen precipitates and Cu–vacancy complex in Czochralski silicon has been investigated by means of Fourier transform infrared spectroscopy (FTIR) and photoluminescence (PL) measurements, respectively. It was found that ramping from low temperature could promote the formation of oxygen precipitates in copper-contaminated Czochralski silicon and the lower the start ramping temperature was, the more oxygen precipitates formed. Moreover, the amount of precipitated oxygen atoms increased with copper contamination temperature. Through the investigation of 0.97 eV PL line related with Cu–vacancy complex, it was revealed that a lower start ramping temperature led to a lower concentration of Cu–vacancy complex and the increase of the copper contamination temperature resulted in the decrease of concentration of Cu–vacancy complex.