Intrinsic Reliability improvement in Biaxially Strained SiGe p-MOSFETs

TL;DR

This paper demonstrates that biaxially strained SiGe p-MOSFETs exhibit improved performance and reliability, including higher hole mobility and reduced degradation, due to material and interface enhancements.

Contribution

It reports the first comprehensive analysis of both performance and reliability improvements in 30nm biaxially strained SiGe p-MOSFETs compared to traditional Si devices.

Findings

40% increase in hole mobility in SiGe channels

~40% reduction in NBTI degradation and gate leakage

Similar degradation mechanisms indicated by identical field acceleration factors

Abstract

In this letter we not only show improvement in the performance but also in the reliability of 30nm thick biaxially strained SiGe (20%Ge) channel on Si p-MOSFETs. Compared to Si channel, strained SiGe channel allows larger hole mobility ({\mu}h) in the transport direction and alleviates charge flow towards the gate oxide. {\mu}h enhancement by 40% in SiGe and 100% in Si-cap SiGe is observed compared to the Si hole universal mobility. A ~40% reduction in NBTI degradation, gate leakage and flicker noise (1/f) is observed which is attributed to a 4% increase in the hole-oxide barrier height ({\phi}) in SiGe. Similar field acceleration factor ({\Gamma}) for threshold voltage shift ({\Delta}VT) and increase in noise ({\Delta}SVG) in Si and SiGe suggests identical degradation mechanisms.