Abnormal slow recovery characteristic of La-doped HfSiOx n-MOSFET bias-temperature instability

We report, for the first time, an abnormal slow recovery characteristic of La-doped HfSiO_x n-MOSFETs subjected to bias-temperature stress. Results show that La introduces a new degradation mechanism having much higher activation energy and slower recovery than the conventional BTI mechanism. In the high temperature regime (>; 100°C), the new mechanism contributes significantly to n-MOSFET degradation. As a result, overall degradation of the n-MOSFET can approach or exceed that of the p-MOSFET although the former exhibits ~1.6× lesser degradation in terms of the conventional BTI mechanism at a given stress condition.