Luminescence Investigations of the Interaction of Oxygen with Dislocations in CZ Si

Abstract

Photoluminescence (PL) spectroscopy and cathodoluminescence (CL) imaging measurements have been carried out to characterize the interaction of oxygen and transition metals with dislocations in CZ Si. The CL and PL spectra recorded from CZ Si samples ([0]=10¹⁷–10¹⁹ cm^-3) deformed at 700°C for 15 minutes contained the characteristic D-band features (D1–D4). As the deformation time increased (>2 hours) the D-band luminescence features were quenched. The quenching of the D-band features was more rapid for the CZ Si samples containing more oxygen. IR absorption measurements showed that there was no detectable changes in the bulk oxygen levels for all the deformation treatments carried out at T=700°C, TEM investigations did not any changes in the dislocation structure or precipitation. It is suggested that the presence of the D-band features in the as-deformed CZ samples is due to the presence of residual transition metal impurities in the starting material. At higher deformation temperatures (T=800°C) no D-bands are observed in the as-deformed state due to oxygen segregation. Following a longer deformation time (>1 hour) the loss of oxygen from solution is observed by IR measurements, subsequent intentional contamination with Fe produces an increase in oxygen loss from solution and an increase in dislocation donor formation.