High frequency characteristics of in-plane-gate transistors

Directly written in-plane-gate (IPG) field effect transistors fabricated using focused ion beams have been proposed and measurements of their dc characteristics have been made. Here, we present for the first time ac measurements up to high frequencies on these transistors. The measurements are made using a direct wafer probing technique. While parasitic elements adversely affect the high frequency operation of the current generation of the IPG transistor, promising results have been obtained. We measure a transconductance of 20 μS which is essentially independent of frequency up to 1 GHz.