Patent ID: 7140942

Claim:
A method for manufacturing an apparatus for emitting electrons, comprising: (a) providing a plurality of emitter tips protruding from an emitter material; (b) depositing a first dielectric layer on the plurality of emitter tips and the emitter material, the first dielectric layer being composed of a dielectric material having an etch reactivity; (c) depositing a dielectric support layer on the first dielectric layer, wherein the dielectric support layer is composed of a dielectric material having a different etch reactivity than the etch reactivity of the first dielectric layer; (d) depositing a gate layer on the dielectric support layer; (e) spinning a photoresist layer on the gate layer and etching the photoresist layer to form an exposed portion of the gate layer over each emitter tip; (f) etching the exposed portion of the gate layer to form an opening in the gate layer and exposing a portion of the dielectric support layer over the emitter tip; (g) etching the exposed portion of the dielectric support layer to form an opening in the dielectric support layer and exposing a portion of the first dielectric layer over the emitter tip, the opening in the dielectric support layer being smaller than the opening in the gate layer; and (h) etching the exposed portion of the first dielectric layer to expose one or more emitter tips by forming a cavity having a conical shape around the one or more emitter tips, the cavity defining an opening in the first dielectric layer that is larger than both the opening in the dielectric support layer and the opening in the gate layer.