Enhancing the Performance of InGaN/GaN Metal–Oxide–Semiconductor High Electron Mobility Transistors for Future Radio-Frequency Power Amplifiers
摘要
The aim of the paper is to develop a methodology for improving critical design parameters, such as drain current (ID) and transconductance (GM), and cutoff frequency (fT) of the GaN-based Metal–Oxide–Semiconductor High Electron Mobility Transistors (GaN-MOSHEMTs). Initially, to improve the device performance of the GaN-MOSHEMT, an InGaN barrier with a high indium (In) mole fraction was used. Owing to its higher carrier concentration at higher In fraction, this study investigated the properties of InGaN/GaN MOSHEMTs, revealing increased ID and GM. Nevertheless, the introduction of higher concentrations in the barrier layer leds to lattice mismatch issues with the GaN channel. To mitigate this, a compositionally optimized In0.30Ga0.70N barrier layer was utilized, ensuring lattice matching with the GaN channel. Additional modifications to the channel layer material, combined with the use of InGaN barriers, led to significant enhancements in DC and RF characteristics. Additionally, various high-k gate dielectrics, including Al2O3, HfO2, ZrO2, and TiO2, were evaluated. Among them, TiO2 demonstrated the best performance, especially at the highest mole fraction (In0.30Ga0.70N), achieving a maximum ID of 0.202 A/mm and a peak GM of 207.4 mS/mm. The consistent increase in ID and GM with rising indium content and higher-k dielectrics confirms the robustness of the proposed design. Moreover, the implementation of a T-shaped gate architecture effectively reduced gate resistance, yielding improved noise performance. The accuracy of these findings was confirmed through detailed simulations performed using the Silvaco DC/RF TCAD tool, providing a comprehensive validation of the theoretical framework.