Tin doping of silicon for controlling oxygen precipitation and radiation hardness

This paper reviews the impact of doping silicon with substitutional tin imp urities on the formation of intrinsic and extrinsic lattice defects. The tw o major topics covered are (i) the effect on the diffusivity and aggregatio n/precipitation of interstitial oxygen in Czochralski (CZ) silicon and (ii) the formation of stable radiation defects in irradiated Sn-doped material. As demonstrated, the compressive stress associated with incorporating a la rge Sn atom on a lattice site is the basic feature governing the interactio ns with point defects. Consequently, Sn acts as a selective vacancy trap, w hile, in contrast, not affecting interstitial reactions. This leads to a re duced formation of oxygen thermal donors in n-type Si and lowers the concen tration of vacancy-oxygen and divacancy centers in irradiated material. Enh anced oxygen precipitation has been noted around 750 degreesC in p-type CZ silicon. Furthermore, specific Sn-related radiation defects are introduced, which question the use of doping with tin as a technique for substrate har dening. (C) 2001 The Electrochemical Society.