The dependence of minority-carrier injection currentJpon applied forward-bias voltage of metalpolysilicon contacts has been calculated within a general treatment of the recombination at grain boundaries. A uniform distribution of interface states in energy at the grain boundaries is assumed throughout. It is found approximately thatJp̃ exp (q V/KT) for (grain-boundary) recombination limited by the supply of minority carriers,Jp̃ exp (q V/KT) or exp (q V/2KT) for high and low grain-boundary interface state densities for recombination limited by the supply of majority carriers, andJp̃ exp (3qV/4KT) for intrinsic recombination (limited equally by holes and electrons). Electrostatic effects of grain-boundary interface states, resulting in a bias dependence of grain-boundary barrier height øg, are significant for interface state densitiesNis> 1010–1011cm−2V−1. depending upon the doping within the grains. The effective diffusion length for the injected minority carriers also shows an appreciable bias dependence, especially for intrinsic recombination, and for majority-carrier limited recombination at high øgand lowNis.Minority-carrier injection dominates the dark current (as it does in ap-njunction) for Schottky-barrier height øb> 0.8 V, for typical grain size d≃10−3cm, interface state densitiesNis≃1013cm−2V−1, and relatively low doping Nd≃1014cm−3.