Patent Number: 
Section: claims

1. An apparatus for improving ion beam quality comprising:an ion source for generating an ion beam, the ion source comprising a faceplate with an aperture for the ion beam to travel therethrough; anda set of extraction electrodes comprising at least a suppression electrode and a high-transparency ground electrode having an overall height H comprising a base height y and a slot height x where the base height y is at least two times less than the slot height x, and a spacing between the suppression electrode and the base of the high-transparency ground electrode in a direction of travel of the ion beam is greater than 70% of the slot height x, and wherein the set of extraction electrodes extract the ion beam from the ion source via the faceplate, and wherein the high-transparency ground electrode together with the spacing is configured to optimize gas conductance between the suppression electrode and the high-transparency ground electrode for improved extracted ion beam quality. 2. The apparatus of claim 1, wherein the high-transparency ground electrode is configured with a base angle θ, and a slot angle δ. 3. The apparatus of claim 2, wherein the base angle θ is 20°. 4. The apparatus of claim 2, wherein the base angle θ is greater than 20°. 5. The apparatus of claim 4, wherein the base angle θ is 40°. 6. The apparatus of claim 1, wherein the high-transparency ground electrode is a single-slot high-transparency ground electrode or a double-slot high-transparency ground electrode. 7. The apparatus of claim 1, wherein the ion source is encased in a housing having a tapered configuration. 8. The apparatus of claim 1, wherein the faceplate is a protruded faceplate in which the faceplate protrudes toward the set of extraction electrodes. 9. The apparatus of claim 1, wherein the suppression electrode is a protruded suppression electrode. 10. The apparatus of claim 1, wherein the high-transparency ground electrode further comprises one or more anchor portions protruding into one or more extraction slots of the high-transparency ground electrode for defining stable plasma boundaries inside of the high-transparency ground electrode. 11. A method for improving ion beam quality comprising:providing an ion source comprising a plasma generator for generating an ion beam and a faceplate with an aperture for the ion beam to travel therethrough; andproviding a set of extraction electrodes comprising at least a suppression electrode and a high-transparency ground electrode having an overall height H comprising a base height y and a slot height x where the base height y is at least two times less than the slot height x, and a spacing between the suppression electrode and the base of the high-transparency ground electrode in a direction of travel of the ion beam is greater than 70% of the slot height x, wherein the set of extraction electrodes extract the ion beam from the ion source via the faceplate, and wherein the high-transparency ground electrode together with the spacing is configured to optimize gas conductance between the suppression electrode and the high-transparency ground electrode for improved ion beam quality. 12. The method of claim 11, wherein the high-transparency ground electrode is configured with a base angle θ, and a slot angle δ. 13. The method of claim 12, wherein the base angle θ is 20°. 14. The method of claim 12, wherein the base angle θ is greater than 20°. 15. The method of claim 14, wherein the base angle θ is 40°. 16. The method of claim 11, wherein the high-transparency ground electrode is a single-slot high-transparency ground electrode or a double-slot high-transparency ground electrode. 17. The method of claim 11, wherein the ion source is encased in a housing having a tapered configuration. 18. The method of claim 11, wherein the faceplate is a protruded faceplate in which the faceplate protrudes toward the set of extraction electrodes. 19. The method of claim 11, wherein the suppression electrode is a protruded suppression electrode. 20. The method of claim 11, wherein the high-transparency ground electrode further comprises one or more anchor portions protruding into one or more extraction slots of the high-transparency ground electrode for defining stable plasma boundaries inside of the high-transparency ground electrode.