AlGaN/GaN-Based Multimetal Gated High-Electron-Mobility Transistor With Improved Linearity

This work proposes a multimetal gated (MMG) architecture to improve the linearity of AlGaN/GaN high-electron-mobility transistor (HEMT). The general idea of this architecture is to use different gate metals along the width of the device. Through experimentally calibrated technology computer-aided design (TCAD) simulation, a selection of metals along with widths that yields the lowest value of third-order transconductance ( ${g}_{m{3}}$ ) has also been estimated. Single-tone large-signal simulation of proposed device exhibits an output-referred 1-dB compression point ( ${P}_{\text {1 dB}}$ ) of 1.81 W/mm, a saturation output power ( ${P}_{\text {sat}}$ ) of 6.91 W/mm, and a maximum power added efficiency (PAE) of 65%, all of which are better than simulations of standard/baseline device structures. Two-tone large-signal simulation shows excellent linearity performance when biased at deep class AB showing OIP3/ ${P}_{\text {dc}}$ of 13.7 dB, which is 6.3 dB higher, and IMD3 of −45.7 dBc, which is 12.9 dB lower than baseline device at ${V}_{\text {DS},{Q}}={28}$ V and ${I}_{D,{Q}}={73}$ mA/mm. These performance matrices attest to the improved linearity performance of the proposed device compared to conventional planar AlGaN/GaN HEMT.