High-Precision Small-Signal Model for Double-Channel–High-Electron-Mobility Transistors Based on the Double-Channel Coupling Effect

This paper presents a new small-signal model for double-channel (DC)–high-electron-mobility transistors, developed through an analysis of the unique coupling effects between channels in devices. Unlike conventional single-channel HEMTs, where electrons only transport laterally in the channel, DC-HEMTs exhibit additional vertical transport between the two channels along the material direction. This double-channel coupling effect significantly limits the applicability of traditional small-signal models to DC-HEMTs. Firstly, the coupling effect between the two channels is characterized by introducing the double-channel coupling sub-model, which consists of RGaN, RAlN, and CAlN. At the same time, by introducing parameters gm_upper and gm_lower, the new model can accurately characterize the properties of double channels. Secondly, initial values for RGaN, RAlN, and CAlN are calculated based on the device’s physical structure and material properties. Similarly, initial values for gm_upper and gm_lower are derived from the device’s DC measurement and TCAD simulation results. Furthermore, a comprehensive parameter extraction method enables the optimized extraction of intrinsic parameters, completing the model’s construction. Finally, validation of the model’s fitting reveals a significantly reduced error compared to traditional small-signal models. This enhanced accuracy not only verifies the precise representation of the device’s physical characteristics but also demonstrates the model’s effectiveness.