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 1.0mol% of KOH for n-GaN is as high as 1600 angstrom/min at an Hg illumination intensity of 35mW/cm². The fabricated GaN MESFET exhibits current saturation at V_ds = 4V and pinch-off at V_gs = -3V with a peak drain current of approx. 240mA/mm at 300K. The DC performance of the device does not change considerably with temperature in the range 300-473K.