Investigation of Positive and Negative Bias Temperature Instability of High-κ Dielectric Metal Gate Metal–Oxide–Semiconductor-Field-Effect-Transistors by Random Telegraph Signal

Abstract

We investigate the impact of positive and negative bias temperature instability (P/NBTI) on the current degradation by using the drain current random telegraph signal (IdRTS) in high-κ gate dielectric and metal-gate MOSFETs. The samples were stressed at typical BTI oxide electric field (∼7 MV/cm) and IdRTS amplitude (ΔIdRTS) distributions were measured before and after P/NBTI stress. It is shown that IdRTS degradation (ΔIdRTS/IdRTS) in NBTI devices exhibits a wider amplitude distribution than the PBTI one. In addition, we trace trapped charge-induced saturation current IDsat degradation in P/NBTI stress. As a result, the statistical analysis indicates that ΔIDsat/IDsat of the p-MOSFET is larger than ΔIDsat/IDsat of the n-MOSFET. Moreover, the lifetime of the device is numerically estimated based on current degradation with or without RTS. We consequently found that P/NBTI lifetime comes worse by considering the effect of RTS.