Simulation Of A Parallel Dual-Metal-Gate Structure For Algan/Gan High-Electron-Mobility Transistor High-Linearity Applications

This article proposes a parallel dual-metal-gate structure (PDM) of AlGaN/GaN high-electron-mobility transistors (HEMTs) for high-linearity applications. Cancellation of the third-order derivative of the I-ds-V-gs curve (g(m)")is achieved by splitting the device into two subcells in parallel with different gate metals. The two subcells have different threshold voltages. When the same bias voltage V-gs is applied, the operating states of the two subcells are independently controlled by the gate bias voltages. The maximum transconductance (g(m,peak)) of the conventional single-metal-gate (SMG) HEMT, double-metal-gate (DMG) HEMT, and PDM-HEMT is all comparable, whereas g(m)" of the proposed structure is 75% lower than that of the SMG HEMT and 47.8% lower than that of the DMG HEMT. The effects of the differences and width ratios of the work function on g(m)" are studied and compared, and a suitably designed PDM-HEMT that can considerably improve linearity without degrading other performance aspects is obtained. This research has significant implications for high-linearity applications.