This paper reviews the impact of doping silicon with substitutional tin impurities on the formation of intrinsic and extrinsic lattice defects. The two major topics covered are ͑i͒ the effect on the diffusivity and aggregation/precipitation of interstitial oxygen in Czochralski ͑CZ͒ silicon and ͑ii͒ the formation of stable radiation defects in irradiated Sn-doped material. As demonstrated, the compressive stress associated with incorporating a large Sn atom on a lattice site is the basic feature governing the interactions with point defects. Consequently, Sn acts as a selective vacancy trap, while, in contrast, not affecting interstitial reactions. This leads to a reduced formation of oxygen thermal donors in n-type Si and lowers the concentration of vacancy-oxygen and divacancy centers in irradiated material. Enhanced oxygen precipitation has been noted around 750°C 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 hardening.

A deep level transient spectroscopy study of defects created by 61 MeV proton irradiation of tin-doped n-type Czochralski silicon is reported. A comparison is made with the deep levels observed in irradiated p–n junction diodes fabricated in n-type float-zone silicon, without tin doping. The main conclusions are that in Sn-doped material, at least two additional deep radiation centers are introduced at 0.29±0.01 and 0.61±0.02 eV below the conduction band. From annealing experiments, it is concluded that these electron traps dissociate below 120 °C, which is lower than observed before for Sn–V related levels. It is demonstrated that the introduction rates of the well-known radiation defects are significantly smaller in Sn-doped material.

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Deep levels in n-type high-purity (HP) detector grade germanium are studied using optical deep level transient spectroscopy (ODLTS). In this technique, optical injection (using light of above band gap energy) from the back ohmic contact together with a suitable sample configuration results in the detection of centers in the minority half of the band gap. Six deep minority carrier traps are detected in typical n-type HP germanium which turn out to be the same defects as found earlier in typical p-type HP germanium as majority carrier traps. These deep defects are mainly copper related. A formula is deduced to calculate concentrations from the ODLTS spectra. It is shown that in n- and p-type HP germanium not only the same defects are present but that their concentrations are also comparable.