InAlN/GaN heterostructure field-effect transistors grown by plasma-assisted molecular-beam epitaxy

We report on the plasma-assisted molecular-beam epitaxy growth and device characteristics of InAIN/GaN heterostructure field-effect transistors (HFETs). The In mole fraction in InAIN was estimated to be 0.15 from the X-ray diffraction profile. The surface root-mean-square roughness of the InAIN layer was less than 3 nm. The room-temperature Hall mobility was 654 cm(2)/V.s, and the sheet electron density was 1.7 x 10(13) cm(-2). The InAIN/GaN HFET, which had a source-drain spacing of 3 mum and a gate length of 1.5 mum, showed a good pinch-off characteristic. The maximum source-drain current density and extrinsic transconductance were 500 mA/mm and 52 mS/mm, respectively.