Dynamic Characterizations of AlGaN-GaN HEMTs with Field-plates using a Double-gate Structure

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