Implications of fin width scaling on variability and reliability of high-k metal gate FinFETs

In this paper, we report a study to understand the fin width dependence on performance, variability and reliability of n-type and p-type triple-gate fin field effect transistors (FinFETs) with high-k dielectric and metal gate. Our results indicate that with decreasing fin width the well-known performance improvement in terms of sub-threshold swing and drain-induced barrier lowering are accompanied by a degradation of the variability and the reliability. As a matter of fact fin width scaling causes (i) higher hot-carrier degradation (HC) in nFinFETs owing to the higher charge carrier temperature for the same internal stress voltages; (ii) worse negative bias temperature instability (NBTI) in pFinFETs due to the increased contribution from the (110) surface; (iii) higher variability due to the non-uniform fin extension doping, as highlighted by applying a novel characterization technique.