Experimental characterization and modeling of electron saturation velocity in MOSFETs inversion layer from 90 to 350 K

From saturation transconductance of devices of 0.25- mu m CMOS technology, the saturation velocity of electrons ( nu /sub sat/) in the inversion layer from 90 to 350 K has been determined. The extracted nu /sub sat/ at 300 K was 7.86*10/sup 6/ cm/s, which is significantly lower than that of bulk silicon ( nu /sub sat-blk/) and has a much weaker temperature dependence. The ratio nu /sub sat-blk// nu /sub sat/ is 1.27 at 300 K, and is increased to 1.68 at 90 K. Consistent values of nu /sub sat/ have been determined for devices of three vastly different MOS technologies, demonstrating the technology independence of nu /sub sat/. The results are useful for developing and testing theoretical carrier transport models, and are of practical importance in estimating the ultimate speed performance of surface MOSFETs. An empirical model for nu /sub sat/ as a function of temperature has also been derived for application in predictive device simulation.<
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