Characterization and modeling of low frequency noise degradation due to NMOS hot electron stress

Low frequency noise (1/f noise) poses a major limitation to analog and radio frequency (RF) integrated circuits (IC) as device dimensions are scaled down. The reduction in device dimensions leads to substantial hot carrier effects and causes increased 1/f noise degradation. This noise degradation has been demonstrated to be detrimental to the functioning of analog mixed signal and RF ICs. Previous work has shown that 1/f noise degradation can be correlated to drain current degradation, but no differentiation of the noise degradation has been made as a function of bias regime or oxide thickness. In this paper, the noise degradation effects in both thin and thick gate oxide NMOS transistors are characterized across different regimes of stress and measurement bias. It is demonstrated that the effect of hot electron stress on 1/f noise in ultra-thin gate oxide transistors is very different from thick gate devices. In addition, it is shown for the first time that the electrical stress regime has a large effect on 1/f noise degradation.