Analyzing E-Mode p-Channel GaN H-FETs Using an Analytic Physics-Based Compact Model

In response to the recent surge of interest in p-channel GaN devices for the development of GaN complementary technology integrated circuits (ICs), a comprehensive model is essential for expediting device design. This article introduces an analytical model for understanding the current-voltage (I-V) characteristics of GaN p-channel FETs (p-FETs). The model is rooted in physics-based expressions of electrostatics, self-consistently solving Schrodinger-Poisson equations, and incorporating Fermi-Dirac statistics, alongside 2-D density of states (2D-DOS) for the 2-D hole gas (2DHG). It further uses drift-diffusion mechanisms to account for hole transport and is validated against experimental data encompassing both enhancement-mode and depletion-mode GaN p-FETs. We further leverage our developed physics-based model to thoroughly analyze the device performance and various device characteristics, including the threshold voltage, in relation to device dimensions and the doping levels within the p-GaN region. This aspect of our model is particularly valuable as it facilitates device optimization. Consequently, process engineers in foundries can use our model to enhance their manufacturing processes when developing p-channel GaN FETs.