Ultrastable emission from a metal–oxide–semiconductor field-effect transistor-structured Si emitter tip

Abstract

A silicon field emitter tip with a dual-gate metal–oxide–semiconductor field-effect transistor (MOSFET) structure was fabricated and demonstrated. The present tip structure is just the same as an n-channel MOSFET whose drain was replaced by a cone-shaped Si tip. Two coplanar gates of 0.3-μm-thick Nb are made on a 0.6-μm-thick thermally oxidized SiO2 insulator between the source and the tip and make inversion layers in a p-type Si substrate under each gate. One of the gates has a 1.8-μm-diam aperture surrounding the tip for extraction of electrons from the tip. The other is 3 μm wide and 300 μm long and is separated by 2 μm from this gate. Ultrastable emission of about 0.3 μA was demonstrated with a single tip for one day.