Effect of jagged field plate structures on DC and RF performance of AlGaN/GaN HEMTs

Abstract

Many field plate structures have been applied to improve the breakdown voltage in high electron mobility transistors (HEMTs). In this paper, the effects of various gate field plate structures on DC and RF performance of AlGaN/GaN HEMTs have been compared. The devices were fabricated on a 3 in sapphire substrate with 0.8 µm gate length, 3 µm source–drain distance, and 50 µm gate width. The results show that the discontinuous field plate structures can improve the cut-off frequency characteristics, but the breakdown characteristics will be weakened. And the increase of the field plate length can improve the breakdown characteristics. Thus, the breakdown characteristics and the cut-off frequency characteristic need to be balanced according to the actual applications by adjusting the length and the area of the field plate structure.