The current density and the ideality factor of the non-radiative band-to-impurity recombination current in a p-n diode is calculated analytically in a very good approximation. The usual approximation of multiplying the maximum recombination rate with the width of the depletion layer is very crude. The ideality factor is found to be <= 2, depending on bias and diffusion voltage. (c) 2005 Elsevier Ltd. All rights reserved.