Physical model of drain conductance, g/sub d/, degradation of NMOSFET's due to interface state generation by hot carrier injection

Degradation of analog device parameters such as drain conductance, g/sub d/, due to hot carrier injection has been modeled for NMOSFET's. In this modeling, mobility reduction caused by interface state generation by hot carrier injection and the gradual channel approximation were employed. It has been found that g/sub d/ degradation can be calculated from linear region transconductance, g/sub m/, degradation which is usually monitored for hot carrier degradation of MOSFET's. The values of g/sub d/ degradation calculated from g/sub m/ degradation fit well to the measured values of g/sub d/ degradation The dependence of the g/sub d/ degradation lifetime on L/sub eff/ has been also studied, this model also provides an explanation of the dependence on L/sub eff/. The model is then useful for lifetime predictions of analog circuits in which g/sub d/ degradation is usually more important than g/sub m/ degradation.>