Combined nanoscale KPFM characterization and device simulation for the evaluation of the MOSFET variability related to metal gate workfunction fluctuations

Abstract

In this work, a more realistic approximation based on 2D nanoscale experimental data obtained on a metal layer is presented to investigate the impact of the metal gate polycrystallinity on the MOSFET variability. The nanoscale data (obtained with a Kelvin Probe Force Microscope, KPFM) were introduced in a device simulator to analyze the effect of a TiN metal gate work functions (WF) fluctuations on the MOSFET electrical characteristics. The results demonstrate that the device characteristics are affected not only by the WF fluctuations, but also their spatial distribution, which is specially relevant in very small devices. The effect on these characteristics of the spatial distribution on the gate area of such fluctuations is also evaluated