Improved Performance of AlGaN/GaN Heterojunction Field-Effect Transistors Using Delta Doping and a Binary Barrier

The improved performance of AlGaN/GaN heterojunction field-effect transistors using a delta-doping approach along with an AlN binary barrier is reported. Low-pressure metalorganic chemical vapor deposition was used to grow the epitaxial heterostructures on semi-insulating SiC substrates. The maximum carrier mobility of µ=1,066 cm2/V-s and sheet carrier density of ns∼2.30×1013 cm-2 yields a large nsµ product of 2.45×1016 V-s. Devices with 0.15 µm gate lengths exhibited a maximum current density of IDSmax=1.82 A/mm (at VG=+1 V) and a peak transconductance of gm=331 mS/mm. Furthermore, fT∼55 GHz and fmax∼115 GHz were measured.