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The current-voltage characteristics of a GaAs vertical field effect transistor (VFET) with an n+ip+in+ planar doped barrier (PDB) launcher has been successfully improved by the optimisation of the launcher structure as well as the reduction of the channel width. Electron-beam direct writing has been used to obtain a small channel width of 0.1 approximately 0.15 mu m, resulting in good pinchoff characteristics. The measured maximum transconductances are 383 and 220 mS/mm at 77 and 300 K, respectively. In spite of a very short channel length (0.1 mu m) and relatively low channel doping density (5*1016 cm-3), a high voltage gain of 15 has been obtained.