Contact modeling and analysis of InAs HEMT transistors

Novel device concepts and better channel materials than Si are required to improve the performance of conventional metal-oxide-semiconductor field-effect transistors (MOSFETs). The exploration of III-V semiconductors is mainly driven by the extremely high electron mobility of the materials. Recently, several researches have demonstrated that III-V high electron mobility transistors (HEMTs) can achieve high-speed operation at low supply voltage for applications beyond Si-CMOS technology. While the intrinsic device performance looks promising, current prototypes are dramatically influenced by high contact resistances. From a modeling point of view the understanding of the intrinsic device performance is now quite advanced, while the understanding of the contacts remains quite limited. Hence, a precise theoretical approach is required to model the contact characteristics. This work investigates the contact resistance physics of InAs HEMT transistors. The Nano-Electronic Modeling Tool (NEMO5) is used to solve the non-equilibrium Green´s function (NEGF) formalism which embeds Schrödinger and Poisson equations self-consistently. For this study a real-space effective mass approximation with a simple phonon scattering is utilized.