A methane-hydrogen (CH4/H-2) reactive ion etching process has been developed for selective gate recess etching of lattice-matched TnGaAs/lnAlAs/InP high-electron-mobility transistors without the need for additional ashing or annealing steps after dry etching. An atomic Force microscope was used for accurate studies of the morphology of the etched 0.2 mu m gate recess. We found that dry etching does not alter the surface roughness significantly for low methane concentrations. Direct current and microwave measurements showed uniform device parameters with a peak transconductance g(mmax) of 700 mS/mm and a unity current gain frequency f(t) of 170 GHz.