Patent Number: 
Section: claims

1. An apparatus, comprising:an ionization chamber for providing ions during a process of ion implantation; andan electron beam source device inside the ionization chamber, the electron beam source device comprising a field emission array having a plurality of emitters for generating electrons in vacuum under an electric field, wherein the field emission array contains an opening in its middle portion; and a cathode inside the electron beam source device configured so that the electrons from the field emission array collide with the cathode, wherein a portion of the cathode goes through the opening in the middle portion of the field emission array in a direction normal to a top surface of the field emission array. 2. The apparatus of claim 1, wherein the field emission array has a cross-section shape selected from a group consisting of a circle, a square and a regular polygon. 3. The apparatus of claim 1, wherein each of the plurality of emitters in the field emission array is a nanogap of at least one metal. 4. The apparatus of claim 3, wherein each of the plurality of emitters in the field emission array is disposed on a dielectric film. 5. The apparatus of claim 1, wherein each of the plurality of emitters in the field emission array comprises at least one carbon nanotube disposed in a void on a dielectric film. 6. The apparatus of claim 1, wherein each of the plurality of emitters in the field emission array is a Spindt array structure, the Spindt array structure comprising a plurality of metal cones, each disposed in a respective cylindrical void on a dielectric film. 7. The apparatus of claim 1, wherein the cathode is configured to emit secondary electrons. 8. The apparatus of claim 1, wherein the ionization chamber is configured to receive at least one dopant gas, and the electrons emitted from the field emission array and the secondary electrons emitted from the cathode collide with the at least one dopant gas for generating plasma comprising ionized dopants. 9. The apparatus of claim 8, further comprising an extraction apparatus for extracting the ionized dopants and forming an ion beam for ion implantation, wherein the extraction apparatus is connected with the ionization chamber. 10. An ion implantation equipment system, comprising:an ion source apparatus for generating an ion beam during a process of ion implantation, the ion source apparatus comprising:an ionization chamber configured to receive at least one dopant gas; andan electron beam source device inside the ionization chamber, the electron beam source device comprising a field emission array having a plurality of emitters for generating electrons in vacuum under an electric field, wherein the field emission array contains an opening in its middle portion; and a cathode inside the electron beam source device configured so that the electrons from the field emission array collide with the cathode, wherein a portion of the cathode goes through the opening in the middle portion of the field emission array in a direction normal to a top surface of the field emission array. 11. The ion implantation equipment system of claim 10, wherein the field emission array has a cross-section shape selected from a group consisting of a circle, a square and a regular polygon. 12. The ion implantation equipment system of claim 10, wherein each of the plurality of emitters in the field emission array is a nanogap of at least one metal disposed on a dielectric film. 13. The ion implantation equipment system of claim 10, wherein each of the plurality of emitters in the field emission array comprises at least one carbon nanotube disposed in a void on a dielectric film. 14. The ion implantation equipment system of claim 10, wherein each of the plurality of emitters in the field emission array is a Spindt array structure, the Spindt array structure comprising a metal cone disposed in a cylindrical void on a dielectric film. 15. The ion implantation equipment system of claim 10, wherein the cathode emits secondary electrons. 16. The ion implantation equipment system of claim 10, wherein the field emission array and cathode are configured so that during use, electrons emitted from the field emission array and the secondary electrons emitted from the cathode collide with the at least one dopant gas for generating plasma comprising ionized dopants. 17. The ion implantation equipment system of claim 10, further comprising an extraction apparatus for extracting the ionized dopants and forming an ion beam for ion implantation, wherein the extraction apparatus is connected with the ionization chamber. 18. An ion generation method in a process of ion implantation, comprising:feeding at least one dopant gas into an ionization chamber; andgenerating electrons from an electron beam source device comprising a field emission array having a plurality of emitters in vacuum under an electric field, wherein the field emission array contains an opening in its middle portion; and a cathode inside the electron beam source device configured so that the electrons from the field emission array collide with the cathode, wherein a portion of the cathode goes through the opening in the middle portion of the field emission array in a direction normal to a top surface of the field emission array. 19. The ion generation method of claim 18, further comprising generating secondary electrons from a cathode in the electron beam source device by directing the electrons emitted from the field emission array toward the cathode; and generating plasma comprising ionized dopants by directing the secondary electrons from the cathode into the ionization chamber. 20. The ion generation method of claim 19, further comprising extracting the ionized dopants in the ionization chamber and forming an ion beam.