Tuning Polarity in WSe<sub>2</sub>/AlScN FeFETs via Contact Engineering
Kwan‐Ho Kim, Seunguk Song, Bumho Kim, Pariasadat Musavigharavi, Nicholas Trainor, Keshava Katti, Chen Chen, Shalini Kumari, Jeffrey Zheng, Joan M. Redwing, Eric A. Stach, Roy H. Olsson, Deep Jariwala
Abstract
Recent advancements in ferroelectric field-effect transistors (FeFETs) using two-dimensional (2D) semiconductor channels and ferroelectric Al 0.68 Sc 0.32 N (AlScN) allow high-performance nonvolatile devices with exceptional ON-state currents, large ON/OFF current ratios, and large memory windows (MW). However, previous studies have solely focused on n-type FeFETs, leaving a crucial gap in the development of p-type and ambipolar FeFETs, which are essential for expanding their applicability to a wide range of circuit-level applications. Here, we present a comprehensive demonstration of n-type, p-type, and ambipolar FeFETs on an array scale using AlScN and multilayer/monolayer WSe 2 . The dominant injected carrier type is modulated through contact engineering at the metal–semiconductor junction, resulting in the realization of all three types of FeFETs. The effect of contact engineering on the carrier injection is further investigated through technology-computer-aided design simulations. Moreover, our 2D WSe 2 /AlScN FeFETs achieve high electron and hole current densities of ∼20 and ∼10 μA/μm, respectively, with a high ON/OFF ratio surpassing ∼10 7 and a large MW of >6 V (0.14 V/nm).