Phosphorus diffusion gettering of substitutional metal contaminants at a small-angle grain boundary in n-type silicon: The case of gold

In this paper, we have studied the effect of phosphorus diffusion gettering on the Au impurities at a model small-angle grain boundary (GB) in n-type silicon by combining spreading resistive profiling and current-voltage characteristic techniques. It is found that at a low level contamination, a single-step phosphorus gettering can be effective for most of Au impurities at the GB by extending the diffusion time. However, at a high level contamination, a two-step phosphorus gettering should be utilized to getter out the gold impurities at the GB. After the effective phosphorus gettering for Au impurities, the GB electrical characteristics can be recovered to the original level.