A study of analog characteristics of CMOS with heavily nitrided NO oxynitrides

Recently, heavily nitrided NO oxynitride has been proposed as an alternative to pure oxide in order to realize high drivability and suppress a large gate leakage current (Fujiwara et al, Digest of IEDM 2000, pp. 227-30, 2000). However, in general, oxynitride has higher interface state density than that of pure oxide, and brings low frequency noise (or 1/f noise) degradation (Kimijima et al., 1999). Thus, analog characteristics under such aggressive doping conditions should be observed carefully for realization of high performance mixed analog and digital LSIs. In this paper, we report analysis of the 1/f noise degradation due to heavily nitrided NO oxynitrides and predict the interface state density value to satisfy 1999 ITRS Roadmap requirements. Additionally, a buried channel type MOSFET is proposed for suppression of the 1/f noise and f/sub T/ degradation.