Defect luminescence from thermal donors in silicon: impact of dopant type and thermal donor concentration

Low-temperature photoluminescence spectroscopy is applied to investigate the difference in luminescence spectra in phosphorous doped and boron doped Cz-Si wafers with different concentrations of thermal double donors. The thermal donors were created by annealing the wafers at 450°C for different periods of time. Phosphorous doped and boron doped samples with the same concentration of thermal donors show distinctly different peaks in their photoluminescence spectra. Phosphorous doped samples exhibit a thermal donor related peak at around 0.88 eV, which is not observed in p-type boron doped samples compensated by thermal donors. Instead, the boron doped samples have a distinct peak at around 0.79 eV. The relative intensity of the thermal donor related peak increases monotonically with the thermal donor concentration for the phosphorus-doped samples.