Control of grown-in defects in czochralski silicon crystals

摘要

In this paper, we will discuss the formation behavior of the OSF-ring in Czochralski silicon crystals, and the annihilation behavior of grown-in voids by high temperature annealing. From an experiment of gold diffusion in CZ-Si wafers including an OSF-ring, it was found that stable nuclei for stacking faults exist in and inside the OSF-ring, and that stacking fault generation enhances the gold diffusion in these regions. In addition, we studied the effect of thermal historiy on the formation of the OSF-ring by applying a crystal growth technique with a modification in its pulling rate. It was found that vacancies are the dominant point defects in and inside the OSF-ring, and that the ring width and size of the OSF nuclei are strongly influenced by the cooling rate at temperatures where grown-in voids and OSF nuclei are formed. Furthermore, we will show that the annihilation process of grown-in voids consists of a dissolution of the inner oxide and shrinkage of voids, in which oxygen atoms and silicon self-interstitials play an important role.