Impacts of short-channel effects on the random threshold voltage variation in nanoscale transistors

Abstract

In this paper, the impacts of device short-channel effects (SCEs) on the random threshold voltage (V TH) variation in nanoscale bulk MOSFETs are investigated. Firstly, the direct relationship between SCEs and random variations are examined. By adopting the electrostatic integrity (EI) as the index for SCEs, clear correlations of device SCEs with random V TH variations are observed, which indicate that the random variations can be reduced by simply improving the SCEs in MOS devices with the same channel doping. In addition, the random dopant fluctuation (RDF) induced σ Vth has a linear relationship with EI and channel doping. Then, considering the contribution of SCEs on RDF modeling, a new normalization method of X VT plot is proposed, which provides a physical way to analyze random V TH variation in nanoscale MOSFETs with different process/device parameters (i.e., with different electrostatic designs).