Patent ID: 8466431

Claim:
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; and 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, 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.