High electron mobility transistor based on a GaN-AlxGa1−xN heterojunction

Abstract
In this letter we report the fabrication and dc characterization of a high electron mobility transistor(HEMT) based on a n‐GaN‐Al0.14Ga0.86N heterojunction. The conduction in our low pressure metalorganic chemical vapor depositedheterostructure is dominated by two‐dimensional electron gas at the heterostructureinterface.HEMT devices were fabricated on ion‐implant isolated mesas using Ti/Au for the source drain ohmic and TiW for the gate Schottky. For a device with a 4 μm gate length (10 μm channel opening, i.e., source‐drain separation), a transconductance of 28 mS/mm at 300 K and 46 mS/mm at 77 K was obtained at +0.5 V gate bias. Complete pinchoff was observed for a −6 V gate bias.