Efficiency of boron gettering for iron impurities in p/p(+) epitaxial silicon wafers

The evaluation of B gettering for Fe impurities in p/p(+) Si epitaxial wafers was carried out, after intentional Fe contamination, by measuring the Fe concentration in the epitaxial layer using deep level transient spectroscopy (DLTS.) As the surface [Fe] before diffusion was increased, [Fe] in epitaxial layer also increased. As B concentration in the p(+) substrate was raised, B gettering efficiency became higher. On comparison of the experimental results with the segregation gettering model, it was concluded that B gettering for Fe does not occur at a high temperature such as 800 degrees C or 1100 degrees C. B gettering for Fe can be inferred to occur below 600 degrees C during the cooling process.