Estimation of NBTI Degradation using IDDQ Measurement

Negative bias temperature instability (NBTI) has emerged as a major reliability degradation factor in nano-scale CMOS technology. In this paper, we analyze the impact of NBTI degradation in both the maximum operating frequency (f
_MAX
) and the total standby leakage current (I
_DDQ
) of digital CMOS circuits. Our analysis shows that due to NBTI, both f
_MAX
and I
_DDQ
reduce with time with a fix exponent of 1/6 (~t
^1/6
). Based on this analysis, we develop temporal f
_MAX
-I
_DDQ
model and apply it to several ISCAS'85 benchmark circuits designed using BPTM 70nm file. Results show that f
_MAX
and I
_DDQ
can reduce by more than 8% and 30% in 3 years operation time, respectively. Furthermore, we show that f
_MAX
and I
_DDQ
degradations are highly correlated throughout the operating lifetime, and using this fact, one can avoid expensive f
_MAX
testing and predict f
_MAX
degradations as a function of I
_DDQ
measures.