Double-gated silicon field emitters

Gated field emission devices have great promise for a number of applications. The electron beams formed by these devices are poorly collimated, however, which limits their utility for certain applications. This article describes an approach to collimating the electron beam and forming a small spot size by using a new chemical–mechanical polishing process to make an electron lens at each field emission tip. Variations in the tip height with respect to the aperture vary βF/βG between 0.16 and 2.67, showing significant sensitivity of the coupling between the focus gate and tip as a function of process variation. The tips exhibit good Fowler–Nordheim behavior and interesting electrostatic properties. Electron spot size reduction greater than ten times is demonstrated.