Absolute standard of diffusion length and lifetime of minority charge carriers in single-crystal silicon

Abstract

A substantial difference in electron recombination cross sections on Fe-B complexes (σ₁) and on activated iron ions (σ₂) in boron-doped single-crystal silicon is used to independently determine the lifetime of electrons in the standard T _st using the surface photo-emf method. Pairs of values of the lifetime T ₁ and T ₂ before and after the decomposition of the Fe-B complexes were measured for each of 600 ingots at arbitrary diffusion length L _cal for the calibrating specimen and were placed on the plane (T ₁, T ₂). At the boundary of the region filled with the points, ingots are presented that are only contaminated with iron ions, so that T ₂/T ₁ = σ₁/σ₂. The true values of L _st and T _st of the calibrating specimen and the ratio σ₁/σ₂ = 12.5 ± 0.5 are determined by selecting a new value of the diffusion length for the calibrating specimen, which straightens the boundary of the region filled with the points after the recalculation of the values of T ₁ and T ₂.