0.1 mu m high performance metamorphic In0.32Al0.68As/In0.33Ga0.67As HEMT on GaAs using inverse step InAlAs buffer

In0.32Al0.68As/In0.33Ga0.67As HEMT structures were grown by molecular beam epitaxy (MBE) on GaAs substrates. An inverse step metamorphic buffer (IS) w as used to reach a relaxation rate close to 98% and a mean cross-hatch of 2 nm. This structure, which has a gate length of 0.1 mu m, exhibits a peak tr ansconductance of 750mS/mm and a current density of 650mA/mm. A current gai n cutoff frequency Ft of 160GHz and a maximum oscillation frequency Fmax of 400GHz were also obtained. These results clearly demonstrate the good elec tron transport properties due to the high relaxation rate and the good filt ering of dislocations.