Present Understanding of Gate Oxide Wearout

Generation of neutral electron traps in the gate oxide leads to degradation in the form of stress-induced leakage current and eventually results in breakdown. We review proposed mechanisms for oxide trap generation and show that the anode hole injection model most likely describes the correct mechanism. Stress-induced leakage is shown to be the result of inelastic trapassisted tunneling of electrons that originate in the cathode conduction band. A framework for modeling time-to-breakdown is presented.