MBE-grown metamorphic In0.52Al0.48As/In0.53Ga0.47As HEMTs on GaAs substrates are presented. A linearly-graded InAlGaAs buffer layer is employed for strain relaxation. A mobility of 9520cm2/Vs and a sheet density of 2.85 × 1012cm-2 are achieved at room temperature. Devices with gate lengths ranging from 0.18 to l.0μm have been fabricated. Large drain currents and extrinsic transconductances with values up to 900mA/mm and 1.1mS/mm, respectively, are reported. For a 0.18μm gate length device, a unity current gain cutoff frequency (fT) of 204GHz is obtained. To the authors' knowledge, this is the highest fT to date for a metamorphic HEMT on GaAs.
ASJC Scopus subject areas
- Electrical and Electronic Engineering