Study of the power performance of gaN based HEMTs with varying field plate lengths

Abstract

In this paper, we report the optimum power performance of GaN based high-electron-mobility-transistors (HEMTs) on SiC substrate with the field plates of various dimensions. The AlGaN/GaN HEMTs are fabricated with 0.6 µm gate length, 3 µm drain-source space. And also, the field plate structures with the lengths of 0.2, 0.3, 0.5, and 0.7 µm have been fabricated on these HEMTs. Great enhancement in radio frequency (RF) output power density was achieved with acceptable compromise in small signal gain. A HEMT of 0.5 µm field plate length and 800 µm gate width is biased under 35 V, at 3 dB gain compression, The results showed that we obtained a continuous wave output power of 36.2 dBm (5.2 W/mm), power-added efficiency (PAE) of 33% and a small signal gain of 11.4 dB from this device. We also could achieve a continuous wave output power of 37.2 dBm (5.2 W/mm), poweradded efficiency (PAE) of 33.7% and a small gain of 10.7 dB from another HEMT with 0.5 µm field plate length and 1000 µm gate width. These results were obtained at 8 GHz without using a via hole technology. The results seem very stunning in this respect. © 2015, North Atlantic University Union. All rights reserved.