Trap-Auger recombination in silicon of low carrier densities

Abstract

We report an analysis of recent accurate room-temperature lifetime measurments τ as a function of injected electron concentration n (equal to injected hole concentration). Instead of the earlier authors' fit to a curve τ-1=a+bn2, we have used τ-1=α+βn+γn2, and have given theoretical formulae for α, β, and γ. An excellent fit for 〈100〉 silicon suggests for γ a sum of the electron and hole band-band Auger coefficients∼10-30 cm 6 s-1, half the value given earlier, but still larger than the accepted value. The importance of the β term is that it indicated that a trap-band Auger effect plays a part. The relevant recombination coefficient, identified from the fit, has the reasonable value∼10 -24 cm6 s-1. The effect seems important in spite of the low residual defect concentration.