3.2 W/mm, 71% PAE AlGaN/GaN HEMT operation at 20 GHz

In this paper we report record AlGaN/GaN HEMT operation at 20 GHz. The 500 μm total gate periphery devices exhibited a continuous wave output power of 3.2 W/mm with a gain of 5.2 dB and an associated power aided efficiency of 71%. To the best of our knowledge, these are the highest reported output power and PAE results for AlGaN/GaN HEMT devices operating at 20 GHz. AlGaN/GaN HEMTs offer increased breakdown, thermal conductivity, electron sheet carrier densities, and saturated electron velocities in comparison to existing group III-V technologies making them well suited for robust operation at frequencies through Ka-band. In order for this material system to meet the requirements for satellite communications and high performance radar, K-band operation is required. The results in this paper show promise for AlGaN/GaN HEMT operation at 20 GHz. The device layers for this study were grown by MOCVD on SiC. 0.15 μm Pt/Au T-gates in a 2 μm source-drain channel were fabricated with electron beam lithography. The devices were passivated with silicon nitride and two levels of interconnect metal including airbridges for external connection.