Statistical observations of NBTI-induced threshold voltage shifts on small channel-area devices

Takashi Sato,  Hiromitsu Awano,  Hirofumi Shimizu,  Hiroshi Tsutsui,  Hiroyuki Ochi
Kyoto Univ.


Performance variability of miniaturized devices will become a major obstacle to designing reliable electronic systems. Temporal degradation of threshold voltages as well as its variation is of increasing concern. In this paper, we present and discuss statistical properties of device degradation measured using an array structure. The circuit is suitable for efficiently collect statistical behavior of degradations and recoveries of very small sized devices. Stair-like changes of threshold voltages found in the measurements suggest that traps and de-traps of carriers may be involved in the degradation process.