【International Papers】Physics-based modeling of surface potential and leakage current for vertical Ga₂O₃ FinFET

      Researchers from the University of Missouri have published a dissertation titled "Physics-based modeling of surface potential and leakage current for vertical Ga₂O₃ FinFET " in Journal of Applied Physics.

ABSTRACT

      Gallium oxide (Ga₂O₃) is a promising ultra-wide bandgap material offering a large bandgap (⁠ >4.7 eV) and high critical electric fields. The increasing demand for electronic devices for high-power applications in electric automobiles, high-performance computing, green energy technologies, etc., requires higher voltages and currents with enhanced efficiency. Vertical transistors, such as fin-shaped field-effect transistors (FinFETs) have emerged to meet the growing need with improved current handling capabilities, reduced resistance, and enhanced thermal performance. However, to fully exploit the Ga2O3 power transistors, precise and reliable physics-driven models are crucial. Therefore, a comprehensive surface potential model has been developed in this work for a vertical Ga₂O₃ FinFET. The electric potential across the channel is explained by analyzing the two-dimensional (2D) Poisson equation employing parabolic approximation. Such a surface potential model is instrumental in determining the performance of the Ga₂O₃ FinFET as it affects the threshold voltage, the drain current, and fringing capacitance. Exploiting the surface potentials, a fringing capacitance model is derived which is crucial in analyzing the speed of the device in compact integrated circuits. In addition, statistical analysis of the Ga₂O₃ FinFET using the Monte Carlo simulation technique is performed to determine the leakage current fluctuation due to doping variations. The validation of the analytical model with experimental results confirms the effectiveness and prospects of the developed models in the rapid development and characterization of next-generation high-performance vertical Ga₂O₃ power transistors.

FIG. 1. Device structure of vertical Ga₂O₃ FinFET, illustrating a two-dimensional schematic with an inset highlighting a three-dimensional view of the fins. The number of fins varied from two to eight.

FIG. 2. An illustration of the fringing fields, with the inner fringing field primarily in the x-direction and the outer fringing field in the y-direction.

FIG. 3. Surface potential of vertical Ga₂O₃ FinFET.

Paper Link：https://doi.org/10.1063/5.0181720