Electron currents injected into SiO2 from p-type Si depletion regions have been measured as a function of the oxide field strength and of the silicon surface potential. These measurements have been made at room temperature and at liquid-N2 temperatures. The oxide field dependence has been compared with a Schottky-emission model suggested by Ning and it has been found that this model must be corrected for oxide scattering. The barrier lowering effect enables us to probe the electron energy distribution from 2.55 to 2.9 eV. The surface potential dependence is not in agreement with Verwey's model but has the form suggested by Pepper; however, Pepper's theory does not give the correct impurity doping dependence. A large increase in oxide current is observed as the temperature is decreased from room temperature to liquid-N 2 temperatures.