On the Potential of Ambipolar Schottky-Based Ferroelectric Transistor Designs for Enhanced Memory Windows in Scaled Devices

Ferroelectric memory devices have seen intense interest over the last decade. However, in heavily scaled devices such as silicon-on-insulator (SOI), FinFETs, and nanowire-based FETs the observed ferroelectric memory window (MW) is heavily degraded owing to the fact that additional majority carriers cannot be sourced as there is no “bulk.” Thus, the device never enters accumulation and polarization switching is suppressed due to the semiconductor channel remaining depleted. Here, we promote an ambipolar Schottky-based ferroelectric transistor (AS-FeFET) as an alternative design. We demonstrate that such devices—owing to their ambipolar nature and thus the ability to source both types of carriers—exhibit MWs that are consistently ~40%–60% larger than conventional devices for the same programming conditions. Although these devices do suffer from a reduced on-current, this tradeoff remains very attractive for many applications.