Trap-Auger recombination in silicon of low carrier densities

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 cm6 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.