Engineering VO, CiOi and CiCs defects in irradiated Si through Ge and Pb doping

Carbon and oxygen associated defects such as VO, CiOi and CiCs are common in electron irradiated silicon. Their presence can affect the material and electronic properties of Si. A way to limit their impact and understand their behavior is through doping with large isovalent dopants. The aim of the present study is to investigate and compare the effect of Ge and Pb doping on VO, CiOi and CiCs defects in electron irradiated Si mainly by using Fourier transform infrared spectroscopy in conjunction with recent density functional theory calculations. It was determined that the production of these defects is reduced by the presence of the isovalent impurity and more significantly for Pb doping as compared to Ge doping. Upon annealing the conversion to secondary defects (in particular VO to VO2 and CiOi to CsO2i) is also affected by the isovalent dopants. Interestingly, the conversion ratio aVO2/aVO is reduced with the increase of the isovalent radius, whereas the aCsO2i/aCiOi is enhanced. Theoretical calculations were used to corroborate these findings.