A metamorphic high electron-mobility transistor with reflowed submicron T-gate for high-speed optoelectronics applications

A metamorphic high electron-mobility transistor (HEMT) manufactured with reflowed submicron T-gate using e-beam lithography for high-speed optoelectronics applications is developed. The In/sub 0.53/Al/sub 0.47/As/InGaAs HEMT uses In/sub x/Al/sub 1-x/As as the buffer layer between GaAs substrate and the InP lattice-matched HEMT structure. The T-gate developed has a gate length of 160 /spl mu/m. The fabricated metamorphic HEMT has a saturation drain current of 280 mA/mm and a transconductance of 840 mS/mm at V/sub DS/ = 1.2 V. Noise figure for 160 /spl mu/m gate-width device is less than 1 dB and the associated gain is up to 14 dB at 18 GHz. The device demonstrates a cut-off frequency f/sub T/ of 150 GHz and a maximum frequency f/sub MAX/ up to 350 GHz. The metamorphic HEMT developed has the potential for high-speed optoelectronics applications.