Ion generator and method for using the same
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsTai-Kun Kao, Tsung-Min Lin, Jen-Chung Chiu, Ren-Dou Lee
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Abstract
Ion generators for ion implanters are provided. The ion generator for an ion implanter includes an ion source arc chamber including an arc chamber housing and a thermal electron emitter coupled to the arc chamber housing. In addition, the thermal electron emitter includes a filament and a cathode, and the cathode has a solid top portion made of a work function modified conductive material including tungsten (W) and a work function modification metal.
Claims20
An ion generator for an ion implanter, comprising:
- an ion source arc chamber comprising an arc chamber housing;
- and
- a thermal electron emitter coupled to the arc chamber housing, wherein the thermal electron emitter comprises a filament and a cathode,
- wherein the cathode has a solid top portion and a hollow bottom portion connected to the solid top portion, and the solid top portion is made of a work function modified conductive material comprising tungsten (W) and a work function modification metal, and the filament is also made of the work function modified conductive material, and a ratio of a thickness of the solid top portion to a thickness of the hollow bottom portion is in a range from about 1:13.4 to about 1:13.9.
A method for generating ions in an ion generator, comprising:
- introducing a reactant gas into an ion source arc chamber;
- heating a filament to emit first electrons from the filament, and the first electrons bombard a cathode to emit second electrons, wherein the cathode is coupled to an arc chamber housing of the ion source arc chamber;
- and
- generating plasma by collision between the reactant gas and the second electrons,
- wherein the cathode comprises a solid top portion and a hollow bottom portion connected to the solid top portion, and the solid top portion is made of a first material comprising tungsten and lanthanum, and a ratio of a thickness of the solid top portion of the cathode to a thickness of the hollow bottom portion of the cathode is in a range from about 1:13.4 to about 1:13.9, and the filament is made of a second material comprising tungsten and lanthanum.
An ion generator for an ion implanter, comprising:
- an arc chamber housing;
- a cathode coupled to a first side of the arc chamber housing, wherein the cathode comprises a solid top portion and a hollow bottom portion;
- and
- a filament fixed in a hollow region surrounded by a cathode wall of the hollow bottom portion of the cathode,
- wherein the solid top portion of the cathode is made of a material comprising tungsten and lanthanum, and a ratio of a thickness of the solid top portion of the cathode to a thickness of the hollow bottom portion of the cathode is in a range from about 1:13.4 to about 1:13.9.
Dependencies are inferred from the claim text.