A Vacuum Multi-Finger Transistor in CMOS Technology

Abstract

Electron filed emission is the process of emission of electrons from a conductor into the vacuum by means of an applied electric field and has a wide range of applications such as displays, electron guns, scanning electron microscopes, high power microwave amplifiers and micro- and nano-vacuum tubes. Vacuum electronic technology became obsolete by its poor reliability characteristics compared to semiconductor technologies. On the other hand, electrons in vacuum can accelerate to close to the speed of light, leading to potentially ultra-high speed devices if the gap between the emitting electrode (Cathode) and an opposing electrode (Anode) is very small (nanometer scale). In such nano-vacuum transistors [1]–[3], fabrication simplicity and reproducibility, high current density, good reliability characteristics and low cost fabrication are of prime importance. In this paper, a high density array of metallic nano-emitters are designed in a standard 45 nm CMOS technology, and are then post-processed using a simple one-step dry etching technology. No lithography is used in the post-CMOS fabrication. Field emission characteristics of the vacuum transistors have been measured. These devices show well-behaved transistor characteristics and are very promising for low-power high-speed applications.