A 36 W CW AlGaN/GaN-power HEMT using surface-charge-controlled structure

We describe high power 36 W CW operation at 30 V using AlGaN/GaN HEMTs on SiC. Surface-charge-controlled structure, consisting of n-type doped thin GaN cap layer on AlGaN/GaN HEMT structure, is used to obtain high gate-drain breakdown voltage and to reduce current collapse. By optimizing threshold voltage of this structure, we obtained a maximum drain current of 1 A/mm and a gate-drain breakdown voltage over 200 V. A 24-mm-wide-gate chip showed output power of 45.6 dBm (36 W) at 2.2 GHz with a liner gain of 9.7 dB.