Investigation of the Impact of BTI Aging Phenomenon on Analog Amplifiers

CMOS technology scaling allows the design of even more complex system but, at the same time, introduces some reliability problems. In particular, aggressively scaled microelectronic technologies are affected by the Bias Temperature Instability (BTI) aging phenomenon that results in an increase of the absolute value of the transistor threshold voltage with aging time and a consequent reduction for the microelectronic circuit reliability. In this paper we estimate the performance degradation caused by BTI on an operational amplifier (OPAMP) in open loop configuration as well as on three other analog amplifiers based on OPAMPs. The results have shown that BTI can seriously impact the performance of the investigated circuits, and that such performance degradation worsens as operating temperature increases. We also briefly describe a possible low-cost monitoring scheme to detect the performance degradation of the OPAMPs caused by BTI. The effectiveness of our monitor has been validated by means of pre-layout electrical simulations, and the results have shown that it can be reliably used to evaluate the OPAMPs aging degradation.