Hot carriers induced degradation in thin gate oxide MOSFETs

The degradation of thin gate oxide (∼100Å) n and p-channel MOSFETs subjected to the substrate hot carrier injection is discussed. The generation of oxide trapped charges is observed to be sublinearly dependent on the applied oxide field, while the generation of interface trapped charges shows a linear dependence on the applied oxide field. The generation rates are found to be a function of carrier fluence and the oxide field, and are independent of the injection current density. The generation of interface traps correlates well with the mobility and subthreshold current degradation. An oxide field around 5MV/cm is found to be a critical value for accelerating device degradation. There is no significant interface trap generation under substrate hot hole injection for the hole fluence up to
2\times10^{17}
/cm
²
. The threshold voltage shifts decrease with increasing applied substrate bias. Possible mechanisms are discussed to account for the experimental data.