The performance of an innovative delta-doped AlGaN/AlN/GaN heterojunction field-effect transistor (HFET) structure is reported. The epitaxial heterostructures were grown on semi-insulating SiC substrates by low-pressure metalorganic chemical vapour deposition These structures exhibit a maximum carrier mobility of 1058 cm2/V s and a sheet carrier density of 2.35 × 1013 cm-2 at room temperature, corresponding to a large nsμn product of 2.49 × 1016 V s. HFET devices with 0.25 μm gate length were fabricated and exhibited a maximum current density as high as 1.5 A/mm (at VG = + 1 V) and a peak transconductance of gm = 240 mS/mm. High-frequency device measurements yielded a cutoff frequency of ft ≃ 50 GHz and maximum oscillation frequency fmax ≃ 130 GHz.
ASJC Scopus subject areas
- Electrical and Electronic Engineering