The design and fabrication of 0.25-μm MESFET's with a channel length of 2.3 pm is reported. A comparison of the effect of the FET geometry (π and parallel gate structures) on device performance is described for the first time. MESFET's were fabricated using a hybrid optical/e-beam lithography process on active layers grown by MBE. FET's show a transconductance of 260 mS/mm and a threshold voltage of -3.0 V. No short-channel effects were observed. From RF measurements, an fmaxof 90–120 GHz was obtained. Excellent device yield across a 3-in wafer and wafer to wafer was achieved.