Lattice location of low-Z impurities in medium-Z targets using ion-induced x rays. II. Phosphorus and sulfur implants in germanium single crystals

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Abstract
In the preceding paper, Paper I, we described an analytical technique, based on ion‐induced x‐ray yields, for detecting low‐Z impurities in medium‐Z targets. In this paper, Paper II, we report the application of this method to the lattice location of impurity atoms. Two systems have been examined to test the method, viz., P and S implants in Gesingle crystals. The channeling effect was applied to the phosphorus and sulfur K x‐ray yields excited by 0.5‐MeV protons. Some 93% of implanted31P (0.7 × 1015 atoms cm−2, room‐temperature implant, 450°C anneal), were found to occupy substitutional sites; the fraction dropped to [inverted lazy s] 63% for an implant dose of 2.7 × 1015 atoms cm−2. Channeling effect results in 〈110〉, 〈111〉, and 〈100〉 directions for Ge(S), implanted at room temperature and annealed at 450°C, prescribe a preferred off‐lattice (> 0.3 Å) site for the sulfur, necessarily different from the regular tetrahedral or hexagonal interstitial sites. For hot (220°C) implantation conditions, poorer crystal annealing and weaker channeling effects were observed.