Controlling base-SiO/sub 2/ density of low-leakage 1.6 nm gate-SiON for high-performance and highly reliable n/pFETs

We report the importance of high-density base-SiO/sub 2/ for nitridation, and demonstrate a low-leakage and highly reliable 1.6 nm gate-SiON without performance degradation in n/pFETs using a radical process. It was found that the high-density 1.6 nm SiO/sub 2/ is ten times more reliable than low-density SiO/sub 2/ in n/pFETs and is suitable as a base layer for radical nitridation as it maintains the surface nitridation of the SiO/sub 2/ and the ideal SiON/Si-substrate interface. The 1.6 nm SiON with the high-density base-SiO/sub 2/ produces comparable drivability in n/pFETs, and has one and half orders of magnitude less gate leakage in nFETs, one order of magnitude less gate leakage in pFETs, and ten times more reliability in n/pFETs than the 1.6 nm SiO/sub 2/.