Capture cross sections of the acceptor level of iron-boron pairs in p-type silicon by injection-level dependent lifetime measurements

Injection-level dependent recombination lifetime measurements of iron-diffused, boron-doped silicon wafers of different resistivities are used to determine the electron and hole capture cross sections of the acceptor level of iron-boron pairs in silicon. The relative populations of iron-boron pairs and interstitial iron were varied by exposing the samples to different levels of illumination prior to lifetime measurements. The components of the effective lifetime due to interstitial iron and iron-boron pairs were then modeled with Shockley-Read-Hall statistics. By forcing the sum of the modeled iron-boron and interstitial iron concentrations to equal the implanted iron dose, in conjunction with the strong dependence of the shape of the lifetime curves on dopant density, the electron and hole capture cross sections of the acceptor level of iron-boron pairs have been determined as (3±2) × 10^-14cm^-2 and (2±1) × 10^-5cm^-2.