Time dependence of radiation-induced interface trap formation in metal-oxide-semiconductor devices as a function of oxide thickness and applied field

Abstract

This work is a study of the formation mechanisms of interface traps (N_it) in metal‐oxide‐semiconductor devices. The time‐dependence of the N_it formation has been measured as a function of oxide thickness following a short radiation pulse. The N_it formation time is found to increase as t^2.6_ox when the gate bias is negative during irradiation and positive afterward. This result is in excellent agreement with predictions of a hydrogen transport model where drift of hydrogen ions (H⁺) is the rate‐limiting step. When the gate bias during irradiation is positive, interpretation of the correlation between data and model suggests that the hydrogen ions are preferentially created near the Si‐SiO₂ interface. Finally, the N_it formation time is found to decrease with increasing oxide field as E^−1.73_ox. This result is compatible with the hydrogen transport model if the average displacement per hop is assumed to be proportional to E^m.