Minority-hole diffusion length in heavily doped silicon

The minority-hole diffusion length in heavily doped n-type silicon wafers was measured in the doping range 1018–1020 cm−3. The experimental method is based on the lateral collection of photogenerated carriers by a semi-infinite junction. Closed form expressions available for this particular two-dimensional geometry greatly simplify the analysis of the experimental results. The results are consistent with an Auger-limited minority-carrier lifetime and a diffusion coefficient that is doping insensitive in the 1018–1020 cm−3 range.