The source of the gate current in MOSFET’s due to an applied drain voltage with the gate grounded is studied. It is found that for 100 Å or thinner oxide, the gate current is due to Fowler-Nordheim (F-N) tunneling of electrons from the gate. With increasing oxide thickness, hot-hole injection becomes the dominant contribution to the gate current. This gate current can cause IDwalkout, which is a decrease in the gate-induced drain leakage current, and hole trapping which becomes important for device degradation study. It can also be used to advantage in EPROM erasure.