The investigation of the stress-induced traps and its correlation to PBTI in high-kdielectrics nMOSFETs by the RTN measurement technique

The PBTI is an important issue in the high-k dielectric nMOSFET devices in the present CMOS technology. In this paper, Random telegraph noise (RTN) technique was employed to investigate the stressed-induced traps and their correlation to the hot carrier and PBTI effects. It was found that the positions of stress-induced traps (SITs) are mostly located in the high-k layer, but not close to the high-k/SiO₂ interface. The SITs under PBTI stress exhibit a larger amount of ΔN_S/N_S in the ΔI_D/I_D fluctuation as a result of the traps which are generated close to the source side and lead to the V_T instability. This new finding is helpful toward the understanding of the BTI effect in high-k gate dielectric MOSFETs.