Relationship between total arsenic and electrically active arsenic concentrations in silicon produced by the diffusion process

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Abstract
The dependences of diffusion coefficient of As, DAs, upon total As concentration, CT, and the relationships between CT and resistivity ρ for several diffusion temperatures are experimentally obtained for the As diffusion into p-type Si from doped polycrystalline-Si sources in the temperature range 850–1050 °C. It is found that the relationship between CT and ρ is dependent upon diffusion temperature for CT above 1020 cm−3. The relationship between CT and electrically active As concentration at diffusion temperature, CA, i.e., CT=CA+(3.2×10−6/n3i) C4A can be obtained, assuming that only electrically active As is mobile and is diffused by the single-level vacancy mechanism, and using the experimental result that the dependence of DAs/Di (Di is the intrinsic diffusion coefficient of As) upon CT/ni (ni is the intrinsic electron concentration) is not influenced by diffusion temperature. Using the above equation, it is found that the relationship between CA and ρ is independent of diffusion temperature, even for CA above 1020 cm−3, and can be approximated for CA above 1020 cm−3 by an empirical equation: ρ=8.7×104 C−2/5A.