Research of Hot Carrier Degradation of Submicron n-channel LDD MOSFETs under Static and Quasi-static Stress Conditions

Hot carrier (HC) injection is one of the main issues on submicron MOSFETs reliability. This article presents experimental evidence that common HC static stress under the maximum impact ionization mode doesn't provide the worst case degradation conditions for submicron n-channel lightly doped drain (LDD) MOSFETs reliability assessment. In addition, LDD affects the devices characteristics degradation behavior. To take this into account two-stage power-law model was used to approximate experimental data over the entire static stress time interval. The developed quasi-static stress technique proved, that the combination of alternate action on the Si/SiO2 interface by hot electrons and holes, demonstrates a greater linear drain current degradation. Moreover, it was revealed that the duration of subthreshold mode increases the rate of the drain current degradation, as well as the time to split components of the two-stage power-law model in the maximum impact ionization mode.