High temperature performance of recessed gate GaN MESFETs fabricated using photoelectrochemical etching process

Recessed gate GaN MESFETs have been fabricated by employing a new photoelectrochemical etching method which utilises a photoresistive mask and KOH based etchant. The etching rate of the etchant with 1.0 mol% of KOH for n-GaN is as high as 1600 A/min at an Hg illumination intensity of 35 mW/cm2. The fabricated GaN MESFET exhibits current saturation at Vds = 4 V and pinch-off at Vgs = –3 V with a peak drain current of ~240 mA/mm at 300 K. The DC performance of the device does not change considerably with temperature in the range 300 – 473 K.