Charge Carrier Mobility and Series Resistance Extraction in 2D Field-Effect Transistors: Toward the Universal Technique

Abstract

2D semiconductor field-effect transistors (2D FETs) have emerged as a promising candidate for beyond-silicon electronics applications. However, its device performance has often been limited by the metal-2D semiconductor contact, and the non-negligible contact resistance (RSD) not only deteriorates the on-state current but also hinders the direct characterization of the intrinsic properties of 2D semiconductors (e.g., intrinsic charge carrier mobility, μint). Therefore, a proper extraction technique that can independently characterize the metal-2D semiconductor contact behavior and the intrinsic properties of a 2D semiconducting layer is highly desired. In this study, a universal yet simple method is developed to accurately extract the critical parameters in 2D FETs, including characteristic temperature (To), threshold voltage (VT), RSD, and μint. The practicability of this method is extensively explored by characterizing the temperature-dependent carrier transport behavior and the strain-induced band structure modification in 2D semiconductors. Technology computer aided design simulation is subsequently employed to verify the precision of RSD extraction. Furthermore, the universality of the proposed method is validated by successfully implementing the extraction to various 2D semiconductors, including black phosphorus, indium selenide, molybdenum disulfide, rhenium disulfide, and tungsten disulfide with top- and bottom-gated configurations.