Dynamic Characterizations of AlGaN/GaN HEMTs With Field Plates Using a Double-Gate Structure

A novel double-gate AlGaN/GaN HEMT, in which an additional top-gate covers the adjacent regions of a normal gate, was proposed and fabricated for the first time to compare the dynamic characteristics of AlGaN/GaN HEMTs with a source field plate (SFP) and a gate field plate (GFP). During the dynamic characterization, the device was configured in two operation modes: One is the SFP mode with the top gate biased at 0 V, and the other is the GFP mode applying the gate pulse signal on the top gate at the same time. Compared with an AlGaN/GaN HEMT without field plates, both GFP and SFP much improve the dynamic performances. Compared with the SFP, the GFP shows better dynamic performances with a ~ 34% reduction of switch-on delay time and ~ 6% reduction of dynamic on-state resistance. Studying the dynamic characteristics and applying negative voltage on the top gate during the off state, the mechanism differences between the GFP and the SFP are discussed in detail.