Hole injection into silicon dioxide films from the polycrystalline‐silicon anode or from the anode/oxide interface is demonstrated to unequivocally occur for any case where electrons are present in the oxide conduction band and where the average electric field in the oxide exceeds 5 MV/cm (thick‐film limit) or the voltage drop across the oxide layer is at least 8 V (thin‐film limit). The hole generation is directly shown to be related to the appearance of hot electrons with kinetic energies greater than 5 eV in the oxide conduction band near the anode region. Monte Carlo simulations confirm that the electron energy distribution at the anode is the controlling variable and that hot hole injection occurs mostly over the anode/oxide energy barrier. ©1996 American Institute of Physics.