The first In049Ga05P/GaAs/In0 2Ga8As micromachined V-groove gate doped-channel FET's (DCFET's) grown by GSMBE were proposed and fabricated successfully. The V-groove gate was formed by anisotropic wet etching of the undoped GaAs layer grown on top of device active layers, followed by standard metal evaporation and lift-off process. Owing to the outward slope of the sidewalls of micromachined V-groove, submicron effective gate length can be easily obtained by normal l-sm UV optical contact lithography. In this way, we simultaneously achieved short gate length (for high speed) and small gate resistance (for low noise) via this "mushroom-like" V-groove gate, without resorting to the expensive and timeconsuming e-beam lithography and the delicate multi-layer photoresist technique. Thanks to the inherent process simplicity, fabricated V-groove gates showed great uniformity and yield in a cost-efficient way, which is essential to industrial mass production. The fabricated DCFET's exhibited a maximum current density 'DS,max of 406 mA/mm, an external transconductance gm,e of 166 mS/mm, and a current gain cut-off frequency T of 13.9 GHz at 300K, all better than those of the counterpart DCFET's of traditional strip gates for contrast experiment. These results suggest that V-groove gate DCFET's are cost-effective devices with submicron gate FETs' performance, and are suitable for low-noise, high-speed, high-power applications.