Analysis of Drain Current Local Variability of an n-Channel E $\delta$ DC MOSFET Due to RDD Considering Inversion Charge and Correlated Mobility Fluctuations

In this paper, we present a physics-based small signal model of drain current local variability due to random discrete dopant effect for an n-type epitaxial delta-doped (EδDC) MOS transistor. Based on the analogy with flicker noise phenomenon, the concept of inversion charge fluctuation with correlated mobility fluctuation (MF) is utilized. The correlated MF has two components. One is due to Coulomb impurity scattering of the inversion carriers with the ionized impurity atoms. The second component is due to the fluctuation of the effective electric field that results in fluctuation of the inversion charges. The model is verified with calibrated technology computer-aided design simulation results for all bias regions for five different device geometries and three different operative temperatures. Impact of channel engineering for reduction of the drain current local variability is studied in detail.