The effect of the denudation anneal on the precipitate dissolution in Czochralski silicon wafers during the three-step internal gettering anneal

Abstract

The effect of the denudation anneal on the precipitate dissolution and defect-free zone formation in Czochralski silicon wafers after a three-step internal gettering anneal was studied. The results imply that the residual precipitates containing three or four oxygen atoms could be the predominant defects influencing the formation of the defect-free zone. Based upon the results from the process simulation model, it is proposed that some residual precipitates having a size less than the critical size could be in a metastable state at high temperatures. Thus during the denudation anneal, the precipitate dissolution occurs primarily in the subsurface region where the critical size is substantially increased due to the oxygen outdiffusion.