The effect of irradiation and heat treatment on the dislocation recombination activity in n-type silicon

Abstract

The variation in the nonequilibrium charge‐carrier lifetime (τ) is studied under irradiation with 60Co γ‐rays (Tirr ⪅ 50 °C) and subsequent isochronal annealing (Tann = 100 to 650 °C) of zone floated and pulled n‐Si (ϱ ≈ 100 Ω cm) containing higher densities of dislocations introduced at plastic deformation (ND = 1 × 102 to 1 × 107 cm−2). τ is measured (Tmeas = 300 K) by the method of conductivity modulation at a point contact at different nonequilibrium charge‐carrier injection levels. The regularities established of the τ‐variation and its dependence on radiation‐thermal treatments of the crystals studied are explained taking into account the interaction of radiation defects and their components, mobile under the experimental conditions, with dislocations. As a result, both the structure of the dislocations and thereby their recombination activity change. The presence of an impuritiy atmosphere near the dislocations is shown to prevent the rearrangement of the dislocation structure under irradiation but to facilitate it at annealing.