Reducing the gate current in vacuum channel field-emission transistors using a finger gate

Abstract

A nanofinger gate vacuum field-emission transistor with a vertical channel (FGVFET) is proposed herein. The reduction of the gate leakage current is investigated to obtain an optimum structure. The proposed three-terminal metal–insulator–metal device with a 43-nm vertical vacuum channel is capable of operating in air ambient and provides a high anode drive current (101 µA), while both the gate and anode voltages are small at about 5 V. Meanwhile, the gate leakage current of the FGVFET is reduced by about sevenfold compared with conventional structures. Also, this vacuum transistor exhibits a low threshold voltage (0.55 V) that is comparable to modern solid-state devices. As a result, a significant cutoff frequency (fT) of 1.13 THz is obtained. Other electrical characteristics of the FGVFET, such as the on–off current ratio and transconductance, are also calculated. The introduced modification could be applied to other vacuum vertical-channel transistors to provide a new class of high-speed low-power transistors for digital applications.