Performance Evaluation and Device Physics Investigation of Negative-Capacitance MOSFETs Based on Ultrathin Body Silicon and Monolayer MoS2.

The proposition of integrating the 2-D materials and ferroelectric negative-capacitance MOSFETs (NCFETs) was expected to have excellent steep slope I – V characteristics due to the combined advantages of both ultrathin body channel material and negative-capacitance effect. Recent experiments demonstrated the excellent steep slope features of 2-D material NCFETs. Therefore, it was important to understand the device physics of this characteristic, its performance projection, and the benchmark with NCFETs based on conventional Group IV materials. In this article, we conducted a computational study of 2-D material NCFETs based on MoS₂ under the nonequilibrium Green’s function (NEGF)-Poisson self-consistent scheme with free-Gibbs energy calculation to judge the operating path in polarization–electric field (P–E) relation. Monolayer MoS₂ (1L-MoS₂) was chosen as channel material while various thickness of ultrathin body silicon (UTB-Si) for benchmark purpose. The results showed an excellent average subthreshold slope (SS) of ~25 mV/dec in 1L-MoS₂ NCFETs compared to ~32 mV/dec of the UTB-Si counterparts. It was found that the steep-slope features in 1L-MoS₂ NCFETs could be attributed to the more optimized capacitance matching in 1L-MoS₂ NCFETs and tunneling currents at the subthreshold region. [ABSTRACT FROM AUTHOR]