Fabrication of a new Si field emitter tip with metal-oxide-semiconductor field-effect transistor (MOSFET) structure

A current-controllable silicon field emitter tip with a metal-oxide-semiconductor held-effect transistor (MOSFET) structure is fabricated. The device has a simple structure in which a conical Si tip is made in the drain region of a MOSFET. The gate performs two roles; one is that of a conventional extraction gate and the other is that of a control gate for the drain current supplied to the tip. The fabrication process is very simple. In order to form n-type regions for the source and drain, only two steps including a self-aligned ion implantation were added to the conventional silicon tip fabrication process. Experimental results showed that the emission current was well controlled and stabilized by the drain current of the MOSFET. Stable emission of about 0.8 mu A was obtained with a single tip. We also discuss a dual-gate MOSFET for further extension of the fabrication process introduced.