MOS-like approach for compact modeling of High-Electron-Mobility Transistor

High-Electron-Mobility Transistor (HEMT) with Al- GaN/GaN gate stack is a promising candidate for high-speed and high-power applications. Recent HEMT compact modeling works have proposed threshold-based [1] and surface-potential-based models [2]. In the latter approach, inversion charge is calculated from the quantum expression of a 2-dimensional electron gas (2DEG). Here, we investigate the possibility to model HEMTs with a MOSFET-like approach whereby quantum confinement is included as an effective bandgap widening in the surface potential equation. We evidence that such a MOSFET-like approach leads to a more accurate description over the whole polarization range, especially in the moderate inversion regime. This analytical model is validated by Poisson-Schrodinger numerical simulations. Furthermore, to address a specific feature of HEMT devices, a field plate model is also presented.