Abstract: Current collapse restrain ability of passivated AlGaN/GaN HEMTs and AlGaN/GaN HEMTs with varying field-plate(FP) length is investigated under different drain bias. The results show that, the passivated HEMTs suffer no current collapse at relatively low but not at higher drain bias, while the HEMTs with optimal field-plate suffer no current collapse for all drain bias used in our tests. Under high drain bias, the FP length plays a crucial role in the current collapse removal. After a thoroughly analysis, it can be concluded that FP structure not only restrains the trapping of virtual gate, but also discharge the virtual gate. Finally, a discharging model of dielectric under FP is presented to explain the effect of FP length on current collapse removal.

Keywords: 
• AlGaN/GaN HEMT /
• field plate /
• current collapse