Ultrahigh-frequency performance of submicrometer-gate ion-implanted GaAs MESFETs

A study of the high-frequency performance of short-gate ion-implanted GaAs MESFETs with gate lengths of 0.3 and 0.5 mu m is discussed. Excellent DC and microwave performance have been achieved with an emphasis on the reduction of effective gate length during device fabrication. From f/sub t/ of 83 and 48 GHz for 0.3-0.5- mu m gate devices, respectively, an electron velocity of 1.5*10/sup 7/ cm/s is estimated. An f/sub t/ of 240 GHz is also projected for a 0.1- mu m-gate GaAs MESFET. These experimental results are believed to be comparable to those of the best HEMTs (high-electron-mobility transistors) reported and higher than those generally accepted for MESFETs.<>