A 0.1-μm T-gate fabricated using e-beam lithography and thermally reflow process was developed and applied to the manufacture of the low-noise metamorphic high electron-mobility transistors (MHEMTs). The T-gate developed using the thermally reflowed e-beam resist technique had a gate length of 0.1 μm and compatible with the MHEMT fabrication process. The MHEMT manufactured demonstrates a cutoff frequency fT of 154 GHz and a maximum frequency fmax of 300 GHz. The noise figure for the 160 μm gate-width device is less than 1 dB and the associated gain is up to 14 dB at 18 GHz. This is the first report of a 0.1 μm MHEMT device manufactured using the reflowed e-beam resist process for T-gate formation.