Analysis of Short-Channel Hafnia-Based FeFET Device Variability Guided by Piezoresponse Force Microscopy

In this article, we present a simulation methodology for studying device-to-device variability in submicrometer planar hafnia-based ferroelectric field-effect transistors (FeFETs) with silicon channels. The simulation methodology is based on thin films of hafnium zirconium oxide (HZO) fabricated under CMOS-compatible conditions, which were characterized using piezoresponse force microscopy (PFM). The PFM images were analyzed using a combination of unsupervised learning with Gaussian mixture models (GMMs) and electrical measurements of polarization-field characteristics of metal–ferroelectric–metal capacitors. The results were directly integrated into an extensive Monte Carlo study based on 2-D device simulations of short-channel front-end FeFETs, where we simulate high- and low-threshold voltage states for 100 total device configurations. From this framework, we quantify how the granular and multiphase nature of ferroelectric HZO contribute to the transport within the semiconductor channel. The results indicate that threshold voltages for both high- and low-threshold states and the subthreshold swings can vary up to about 400 mV and 20 mV/dec, respectively.