AlGaN/GaN Round-HEMTs on (111) silicon substrates

AlGaN/GaN Round-HEMTs on silicon substrates have been realised and their static charcteristics investigated. The AlGaN/GaN (x = 0.23) material structures were grown on (111) p-Si by LP-MOVPE. Devices with 0.3 mu m gate length exhibit a saturation current of 0.82 A/mm, a good pinch-off and a peak extrinsic transconductance of 110 mS /mm. Highest saturation current reported so far and static output characteristics up to 20 V demonstrate that the devices are capable of handling 16 W/mm of static heat dissipation without any degradation of their performance.