US 5,630,741 A · Fabrication process for a field emission display cell structure

Abstract

A lateral-emitter field emission device has a thin-film emitter cathode 50 which has thickness of not more than several hundred angstroms and has an edge or tip 110 having a small radius of curvature. To form a novel display cell structure, a cathodoluminescent phosphor anode 60 is positioned below the plane of the thin-film lateral-emitter cathode 50, allowing a large portion of the phosphor anode's top surface to emit light in the desired direction. An anode contact layer contacts the phosphor anode 60 from below to form a buried anode contact 90 which does not interfere with light emission. The anode phosphor is precisely spaced apart from the cathode edge or tip and receives electrons emitted by field emission from the edge or tip of the lateral-emitter cathode, when a small bias voltage is applied. The device may be configured as a diode, triode, or tetrode, etc. having one or more control electrodes 140 and/or 170 positioned to allow control of current from the emitter to the phosphor anode by an electrical signal applied to the control electrode. In a particularly simple embodiment, a single control electrode 140 is positioned in a plane below the emitter edge or tip 110 and automatically aligned to that edge. The display cell structure may be repeated many times in an array, and the display cell structure of the invention lends itself to novel array structures which are also disclosed. A fabrication process is disclosed using subprocess steps S1-S19 similar to those of semiconductor integrated circuit fabrication to produce the novel display cell structures and their arrays. Various embodiments of the fabrication process allow the use of conductive or insulating substrates 20 and allow fabrication of devices having various functions and complexity.

Claims24

Dependent claims

A method of fabricating a field emission device, comprising the steps of:

(a) providing a substrate;
(b) disposing a first insulating layer upon said substrate, said first insulating layer being of predetermined thickness;
(c) disposing a first conductive layer having a thickness of only several hundred angstroms relative to the upper surface of said substrate, said first conductive layer being disposed so as to extend parallel to the upper surface of said substrate, said first conductive layer having a bottom surface defining an emitter plane;
(d) providing an opening through said first insulating layer and through said first conductive layer, thereby forming an edge of said first conductive layer;
(e) disposing a conformal layer of material only on the walls of said opening provided in step (d), said conformal layer being of predetermined thickness;
(f) filling said opening partially with a phosphor layer such that said conformal layer spaces said phosphor layer from said edge of said first conductive layer, said predetermined conformal layer thickness equaling a desired spatial distance between said edge of said first conductive layer and said phosphor layer, and said phosphor layer being of a thickness less than said predetermined thickness of said first insulating layer disposed in step (b), said phosphor layer thereby having a top surface lying below said emitter plane;
and
(g) providing means for applying an electrical bias voltage to said first conductive layer and to said phosphor layer, said bias voltage to be applied being sufficient to cause cold cathode emission current of electrons from said edge of said first conductive layer to said phosphor layer.

5 more elements

A method of fabricating a field emission device, comprising the steps of:

(a) providing an insulating substrate;
(b) disposing a first conductive layer upon said insulating substrate, said first conductive layer being transparent;
(c) disposing a first insulating layer upon said substrate, said first insulating layer being of predetermined thickness;
(d) disposing a second conductive layer having a thickness of only several hundred angstroms relative to the upper surface of said substrate, said second conductive layer being disposed so as to extend parallel to the upper surface of said substrate;
(e) providing an opening through said first insulating layer and through said second conductive layer, thereby forming an edge of said second conductive layer;
(f) disposing a conformal layer of material only on the walls of said opening provided in step (d), said conformal layer being of predetermined thickness;
(g) filling said opening at least partially with a phosphor layer such that said conformal layer spaces said phosphor layer from said edge of said second conductive layer, said predetermined conformal layer thickness equaling a desired spatial distance between said edge of said first conductive layer and said phosphor layer, and said phosphor layer being of a thickness less than said predetermined thickness of said first insulating layer disposed in step (c);
and
(h) providing means for applying an electrical bias voltage to said second conductive layer and to said phosphor layer, said bias voltage to be applied being sufficient to cause cold cathode emission current of electrons from said edge of said second conductive layer to said phosphor layer.

6 more elements

A method of fabricating a field emission device, comprising the steps of:

(a) providing a flat substrate;
(b) disposing a layer of insulator on said substrate to form a first insulating layer having a top surface;
(c) patterning said first insulating layer and etching said first insulating layer to form a first opening for conductive material;
(d) disposing said conductive material in said first opening to form a buried anode contact layer;
(e) disposing a conductive layer selectively on said top surface of said first insulating layer, and spaced from said buried anode contact layer to form a control electrode layer;
(f) disposing a layer of insulator to form a second insulating layer over said control electrode layer;
(g) disposing a conductive layer having a thickness of only several hundred angstroms over said second insulating layer to form a thin emitter layer;
(h) disposing a third insulating layer over said thin emitter layer;
(i) providing an opening through said third insulating layer, said thin emitter layer, said second insulating layer, and said control electrode layer, thereby forming an emitter edge of said thin emitter layer and a control electrode edge of said control electrode layer while providing an opening to the top surface of said buried anode contact layer;
(j) disposing a conformal layer of material only on the walls of said opening, said conformal layer having a predetermined thickness to form a spacer;
(k) disposing a phosphor layer on said buried anode contact layer within said opening provided in step (i) to a predetermined thickness less than the distance from the top surface of said buried anode layer to the bottom surface of said thin emitter layer;
(l) removing said conformal layer from between said emitter edge and said phosphor layer;
(m) providing means for applying an electrical bias voltage to said emitter layer and to said buried anode contact layer, said bias voltage to be applied being sufficient to cause cold cathode emission current of electrons from said emitter edge to said phosphor layer;
and
(n) providing means for applying a signal voltage to said control electrode layer, said signal voltage being sufficient to control said current of electrons.

12 more elements

A method of fabricating a field emission device, comprising the steps of:

(a) providing an insulating substrate;
(b) disposing a first conductive layer upon said insulating substrate, said first conductive layer being transparent;
(c) disposing a second conductive layer spaced from said first conductive layer, said second conductive layer being transparent;
(d) disposing a first insulating layer upon said first conductive layer, said first insulating layer being of predetermined thickness;
(e) disposing a third conductive layer having a thickness of only several hundred angstroms relative to the upper surface of said substrate, said third conductive layer being disposed so as to extend parallel to the upper surface of said substrate;
(f) disposing a second insulating layer on said third conductive layer;
(g) disposing a fourth conductive layer on said second insulating layer, said fourth conductive layer being transparent;
(h) providing an opening through said first insulating layer and through said third conductive layer, thereby forming an edge of said third conductive layer;
(i) disposing a conformal layer of material only on the walls of said opening provided in step (h), said conformal layer being of predetermined thickness;
(j) filling said opening partially with a phosphor layer such that said conformal layer spaces said phosphor layer from said edge of said second conductive layer, said predetermined conformal layer thickness equaling a desired spatial distance between said edge of said first conductive layer and said phosphor layer, and said phosphor layer being of a thickness less than said predetermined thickness of said first insulating layer disposed in step (d);
(k) providing means for applying an electrical bias voltage to said third conductive layer and to said phosphor layer, said bias voltage to be applied being sufficient to cause cold cathode emission current of electrons from said edge of said third conductive layer to said phosphor layer;
and
(l) providing means for applying electrical signals to said second conductive layer and to said fourth conductive layer, each of said electrical signals to be applied being sufficient to control said current of electrons.

10 more elements

Dependencies are inferred from the claim text.

Fabrication process for a field emission display cell structure

Life of this patent

Fabrication process for a field emission display cell structure

Life of this patent

Abstract

Claims24