A model for gate oxide wear out based on electron capture by localized states

A model is proposed which addresses the effects of the oxide electric field and anode bias as well as the role of hydrogen in the trap generation process. The oxide wear-out phenomenon is considered as a multistep process initiated by the capture of injected electrons by localized states in SiO2. The captured electron significantly weakens the corresponding Si-O bond, which becomes unstable with respect to the applied electric field and temperature. The hydrogen presented in the oxide (due to anode hydrogen release process) prevents restoration of the broken bond that leads to the generation of a neutral E' center. The model describes the charge-to-breakdown dependence on the electron fluence and energy, electric field, temperature, and oxide thickness. (C) 2002 American Institute of Physics.