How good are 2D transistors? An application-specific benchmarking study

Abstract

The research community has invested heavily in semiconducting two-dimensional (2D) materials, such as transition metal dichalcogenides (TMDs). Their stability when scaled down to a few atoms thick makes them attractive candidates to replace or supplement silicon in many future technologies. Although this sentiment is prevalent, demonstrations of 2D field-effect transistors (FETs) often do not present their data in a way that enables a straightforward comparison. For example, some papers solely use mobility as the figure of merit, while others focus on unnormalized device on-current. Here, we benchmark the performance of a selection of 2D FETs with field-corrected metrics that allow a more accurate projection of their potential; while the demonstrated methods are by no means comprehensive, they provide insight into improved benchmarking of 2D FETs going forward. Importantly, we show that appropriate benchmarking requires consideration of the specific application, with the three dominant potential application areas of front-end-of-line (FEOL) high-performance FETs, back-end-of-line (BEOL) 3D-integrated FETs, and low-cost thin-film FETs (or TFTs) each demonstrated. We find that 2D materials have the potential to compete with silicon as the channel in scaled FEOL high-performance devices. Meanwhile, in BEOL applications, FETs from in situ synthesized 2D materials have performance limited by their low crystal quality – a result of the stringent thermal budget of BEOL fabrication, which necessitates the use of transferred 2D materials. In the TFT area, 2D materials are simpler to fabricate than their silicon-based counterparts and they are competitive with other material alternatives. As promising as these findings are, there remain many hurdles for 2D materials to overcome, including poor reliability, performance variability, and fabrication scalability. Continuous research effort, combined with appropriate benchmarking, is strongly encouraged.