Method of Decoupling the Bias Temperature Instability Component from Hot Carrier Degradation in Ultrathin High-$k$ Metal--Oxide--Semiconductor Field-Effect Transistors

Hot-carrier (HC) degradation becomes more critical as the channel length is reduced. Furthermore, both positive and negative bias temperature instabilities (PBTI and NBTI, respectively) are significant in high-$k$ devices. Under HC stress, BTI caused by the vertical electric field is unavoidable. The decoupling of the BTI component from HC degradation is necessary to predict device lifetime more accurately. In this study, a new decoupling method of HC degradation is proposed. By using the relation between $\Delta V_{\text{th}}$ and $J_{\text{g}}$, the BTI component can be decoupled from the degradation under $V_{\text{g}}=V_{\text{d}}$ stress. The application of our method to HfSiON metal--oxide--semiconductor field-effect transistors (MOSFETs) is demonstrated. The channel length dependence of each component shows the improvement resulting from the decoupling method. Furthermore, the activation energy of the NBTI component in HC degradation coincides with that of NBTI.