Submicron-gate In0.52Al0.48As/In0.53Ga0.47As/In0.52Al0.48As heterojunction metal-semiconductor field-effect transistors grown by molecular beam epitaxy

We report the dc and microwave performance of i-InAlAs/n+-InGaAs/i-InAlAs heterojunction metal-semiconductor field-effect transistors (MESFETs) with gate lengths from 0.25 to 0.35 μm. At 10 GHz, an extrinsic transconductance (gm) of 507 mS/mm, a current gain cutoff frequency (ft) of 49.5 GHz, and a power gain cutoff frequency (fmax) of 70.5 GHz were observed for a 0.25 μm gate device. For a 0.3 μm gate device, a gm of 545 mS/mm, an ft of 42 GHz, and an fmax of 114 GHz were measured. Output conductance as low as 7.7 mS/mm was measured. The voltage gain for measured devices is well above 20 for a wide range of bias conditions.