AlGaN/GaN HEMTs on (111) silicon substrates

AlGaN/GaN HEMTs on silicon substrates have been fabricated and their static and small-signal RF characteristics investigated. The AlGaN/GaN material structures were grown on (111) p-Si by LP-MOVPE. Devices exhibit a saturation current of 0.91 A/mm, a good pinchoff and a peak extrinsic transconductance of 122 mS/mm. A unity current gain frequency of 12.5 GHz and f(max)/f(T) = 0.83 were obtained. The highest saturation current reported so far, static output characteristics of up to 20 V and breakdown voltage at pinchoff higher than 40 V demonstrate that the devices are capable of handling similar to16 W/mm static heat dissipation.