A Comparative Study of NBTI and PBTI Using Different Experimental Techniques

Degradation in planar high-k metal gate pand n-channel MOSFETs, respectively, under negative bias temperature instability (NBTI) and positive bias temperature instability (PBTI) stress is studied using different characterization methods. Ultrafast measure stress measure (UF-MSM) method with a measurement delay of a few microseconds is used to characterize the threshold voltage shift (ΔVT). Gated-diode or direct current IV is used to directly estimate the trap generation (TG) during BTI, after correcting for the measurement inconsistencies. BTI experiments are performed under DC stress at different stress bias (VG-STR) and temperature (T) values also under AC stress at different pulse duty cycle (PDC) and frequency (f) values. Measured ΔVT as well as TG show remarkable similarities between NBTI and PBTI stress, under both DC and AC stress. It is shown that TG dominates NBTI and PBTI degradation under both DC and AC stress.