This paper reports new homogeneous hot-electron injection data at 300 K and 77 K covering applied voltages from well below to well above the Si-SiO2 barrier height, and a wide range of oxide fields. We found that, in contrast to the MOSFET case, homogeneous injection shows two different regimes for accelerating voltages below and above the barrier height. A simple interpretation of the data is proposed, and supported by Monte Carlo simulations of the injection experiment. Modeling issues and possible implications of the results for future devices and MOSFET gate currents are briefly discussed.