Method for making a field emission device

Claim 1

A method for making a field emission cathode comprising the steps of: depositing a cathode electrode on a substrate; depositing an insulating layer on top of the deposited cathode electrode; depositing a gate electrode on top of the deposited insulated layer; forming a cavity through the deposited gate electrode and insulating layer; depositing a parting, layer on the gated electrode layer and the opening perimeter for narrowing the opening; Then forming a truncated buffer layer on the cathode electrode by deposition of a material from a source outside the cavity while the cavity opening is being simultaneously narrowed, thereby giving a conical shape to the buffer layer; forming a field emission cathode tip on the truncated buffer layer by deposition of metal from a source outside the cavity while the cavity opening is being simultaneously narrowed to complete closure, thereby giving a conical shape to the cathode tip; and then removing the parting layer and all layers deposited on it.

Claim 2

A method for making a field emission cathode comprising the steps of: depositing a cathode electrode on a substrate; depositing an insulating layer on top of the deposited cathode electrode; depositing a gate electrode on top of the deposited insulated layer; forming a cavity through the deposited gate electrode and insulating layer; depositing a parting, layer on the gated electrode layer and the opening perimeter for narrowing the opening; Then forming a truncated buffer layer on the cathode electrode by deposition of a material from a source outside the cavity while the cavity opening is being simultaneously narrowed, thereby giving a conical shape to the buffer layer; forming a field emission cathode tip on the truncated buffer layer by deposition of metal from a source outside the cavity while the cavity opening is being simultaneously narrowed to complete closure, thereby giving a conical shape to the cathode tip; and then removing the parting layer and all layers deposited on it.

Claim 3

A method for making a field emission cathode comprising: a first main step comprising steps of: depositing a cathode electrode on a substrate, depositing an insulating layer on top of the deposited cathode electrode, depositing a gate electrode on top of the deposited insulating layer, and forming a cavity through the deposited gate electrode and insulating layer; a second main step of depositing a metal parting layer on top of the deposited gate electrode layer and on the perimeter of the gate electrode layer forming the cavity opening, thereby narrowing the opening; a third main step of forming a truncated buffer layer on the cathode electrode by deposition of a metal through the cavity opening from a source outside the cavity, which forms a simultaneous barrier layer on the parting layer, narrowing the cavity opening as the barrier layer thickness increases, resulting in the simultaneous decrease in the diameter of the truncated buffer layer being formed on the cathode electrode; a fourth main step of forming a cone-shaped field emission cathode tip on the truncated buffer by deposition of a metal through the cavity opening from a source outside the cavity, which simultaneously forms another barrier layer on top of the barrier layer deposited during the third main step, narrowing to complete closure the cavity opening as the barrier layer thickness increases, thereby simultaneously decreasing the diameter of the material being deposited on top of the truncated buffer formed in the third main step to a point when the opening is just about closed; and a fifth main step of removing the parting layer with all barrier layers attached.

Claim 4

A method for making a field emission cathode comprising: a first main step comprising steps of: depositing a cathode electrode on a substrate, depositing an insulating layer on top of the deposited cathode electrode, depositing a gate electrode on top of the deposited insulating layer, and forming a cavity through the deposited gate electrode and insulating layer; a second main step of depositing a metal parting layer on top of the deposited gate electrode layer and on the perimeter of the gate electrode layer forming the cavity opening, thereby narrowing the opening; a third main step of forming a truncated buffer layer on the cathode electrode by deposition of a metal through the cavity opening from a source outside the cavity, which forms a simultaneous barrier layer on the parting layer, narrowing the cavity opening as the barrier layer thickness increases, resulting in the simultaneous decrease in the diameter of the truncated buffer layer being formed on the cathode electrode; a fourth main step of forming a cone-shaped field emission cathode tip on the truncated buffer by deposition of a metal through the cavity opening from a source outside the cavity, which simultaneously forms another barrier layer on top of the barrier layer deposited during the third main step, narrowing to complete closure the cavity opening as the barrier layer thickness increases, thereby simultaneously decreasing the diameter of the material being deposited on top of the truncated buffer formed in the third main step to a point when the opening is just about closed; and a fifth main step of removing the parting layer with all barrier layers attached.