High-Performance AlGaN/GaN Enhancement-Mode High Electron Mobility Transistor by Two-Step Gate Recess and Electroless-Plating Approaches

In this work, an AlGaN/GaN enhancement-mode high electron mobility transistor (HEMT) with two-step gate recess and electroless plating (EP) approaches is reported. Scanning electron microscopy and atomic force microscopy surface analysis are used to analysis the related properties of the EP-gate structure. A positive threshold voltage V th of 0.68 V is obtained for the enhancement-mode EP-HEMT. In addition, a traditional HEMT based on thermal-evaporation gate is compared for the demonstration of the studied EP-HEMT with the improved performance, such as a higher maximum drain saturation current of 228.9 mA/mm, a higher maximum transconductance of 107.2 mS/mm, a lower gate leakage current of 1.2 × 10 –7 mA/mm, and a higher ON/OFF drain current ratio of 4.57 × 10 5 .