New observations on the random telegraph noise induced Vth variation in nano-scale MOSFETs

In this paper, random telegraph noise (RTN) induced ΔV_th variation under the worst bias condition is experimentally investigated. The results show that ΔV_th significantly increases with the gate bias, which confirms that RTN amplitude should be evaluated and modeled under full bias swing. Moreover, the impacts of BTI aging on RTN are further studied. The experimental results show that RTN amplitude after aging is still at the same range as that under “time zero” condition. For the device size used in the study, no extra guard-band in design margin seems necessary if time0 variation can capture such RTN variations. Aging is generally modeled separately. Lastly, to understand the impacts of random switching behavior of individual traps, RTN induced time dependent performance-to-performance variation (PPV) is also studied. The results show that the worst bias condition of PPV could shift to the point of Vg<;VDD, due to the other factor of trap occupancy rate (TOR).