Effect of tin on point defects and oxygen precipitation in Czochralski silicon: Experimental and theoretical studies

The effect of tin (Sn)-doping on point defects and oxygen precipitation (OP) in Czochralski (CZ) silicon has been investigated by experiment and theoretical calculations based on density functional theory (DFT). It is found that Sn plays different roles in affecting OP according to the amount of introduced vacancies. That is, Sn suppresses OP in vacancy-lean CZ silicon but promotes OP in vacancy-rich CZ silicon. The effects of Sn-doping on the formation and annihilation of point defects as well as on the evolution of vacancy- and oxygen-related complexes have been systematically studied using DFT calculations. Based on the experimental and theoretical results, it is postulated that Sn atoms in silicon act as vacancy reservoirs which modify the formation and annihilation of vacancies as well as the evolution of vacancy-related complexes. The mechanism for the different roles of Sn in affecting OP is discussed based on the DFT calculations.