Scalable Compact Model for High-frequency GaN-HEMTs.

This paper presents a compact model for GaN-HEMT high-frequency operations that is scalable over dc bias, geometry, and doping concentrations. Specifically, a "surface-potential-based" compact model for (intrinsic) GaN-HEMTs is extended to model the "sub-surface" (substrate) and access (extrinsic) regions of the GaN-HEMT for capturing its nonlinear current/charge behaviors that are important at high-frequency operations. A quiescent-bias (Q-point) scalable RF model is not easily achievable by conventional sub-circuit approaches in which different R/C element values need to be extracted at different Q-points. Preliminary results show that the developed RF model is scalable for different Q-points as well as gate and gate-source/drain lengths and substrate doping concentrations without refitting the model. The scalable GaN-HEMT RF model is validated in comparison with S-parameters from numerical simulations and available measurement data. The proposed concepts and methodology will lead to new approaches to RF compact modeling, and it can be extended to Si-MOSFETs RF modeling as well.