Variability in Planar FeFETs-Channel Percolation Impact

We examine the origins of threshold voltage (V-TH) variability in planar ferroelectric FETs (FeFETs) considering process variations and source-drain channel percolation. Using a percolation-aware physics-based multidomain FeFET model, we are able to capture the V-TH statistics measured on fabricated devices across different channel dimensions. We show that the bimodal V-TH distribution observed in large devices can be explained by percolation, while the transition to monomodal distribution in scaled devices is qualitatively reproduced by the overlapping Pelgrom-type and percolative variabilities in the model. We further demonstrate that in terms of device geometry, the percolation-related FeFET V-TH variability is minimized for a channel aspect ratio equal to 1.

Automated summary

We investigate the origins of threshold voltage (V-TH) variability in planar ferroelectric FETs (FeFETs) by considering both process variations and source-drain channel percolation. By using a percolation-aware physics-based multidomain FeFET model, we are able to accurately capture the measured V-TH statistics across various channel dimensions in fabricated devices. Our findings suggest that the bimodal V-TH distribution observed in large devices can be explained by percolation, while the transition to a monomodal distribution in scaled devices is qualitatively reproduced by the overlapping Pelgrom-type and percolative variabilities in the model. Furthermore, we demonstrate that the percolation-related FeFET V-TH variability is minimized when the channel aspect ratio is equal to 1 in terms of device geometry.