Phonon Scattering Effects with Introduced Strain and High-k Dielectrics on Electrical Properties of Molybdenum Disulfide Field-Effect Transistors

As electronic devices scale down to atomic-level quasi-two-dimensional (2D) nanosheets, molybdenum disulfide (MoS 2 ) has emerged as a promising channel material due to its superior electronic and mechanical properties. However, the integration of MoS 2 into next-generation transistors faces critical challenges, primarily due to phonon scattering, which degrades current flow and limits device performance, particularly as channel lengths become shorter and operating temperatures rise. To address this issue, this study investigates the combined effects of strain engineering and high-k dielectric materials on MoS 2 field-effect transistors (FETs). Utilizing a modified ballistic FETToy model with a top-of-the-barrier (ToB) model approach, phonon scattering was incorporated via transmission probability, which is dependent on both channel length and temperature. Strain effects were modeled by adjusting the electron effective mass. The results indicate that phonon scattering reduces the current by up to 43.5% at a channel length of 10 nm compared to ballistic operation, with increased impact at elevated temperatures. Compressive strain mitigates these effects, increasing the current by 13.1% at 10 nm, while tensile strain further suppresses performance. High-k dielectrics also substantially improve current flow and, when used in conjunction with compressive strain, yield a 22.4% enhancement in current relative to the unstrained ballistic reference. These results demonstrate the effectiveness of integrating strain and dielectric optimization within a quasi-ballistic modeling framework, providing a systematic approach for assessing ultra-scaled MoS 2 FET performance.