Focused ion beam system

A focused ion beam system, comprising:

• a plasma generator which produces ions in a plasma generation region;
• a first electrode positioned adjacent to the plasma generation region and having a first aperture formed therein;
• a second electrode in a spaced relation to the first electrode and having a second aperture formed therein and aligned with the first aperture, the first and second electrodes having voltages applied thereto to extract ions from the plasma generation region through the first aperture and on through the second aperture;
• additional acceleration and focusing electrodes following the second electrode and having aligned apertures therethrough for accelerating and focusing ions extracted from the plasma generation region to produce a final ion beam;
• wherein the ratio of the first aperture diameter to the first electrode thickness at the aperture is sufficiently large to produce an ion current through the first aperture of at least about 1 .mu.A.

A method of producing a focused ion beam, comprising:

• generating a plasma;
• extracting ions from the plasma through a first aperture in a first electrode, the ratio of the first aperture diameter to the first electrode thickness at the aperture being sufficiently large to produce an ion current through the first aperture of at least about 1 .mu.A;
• passing the ions extracted through the first aperture through a second aperture in a second electrode;
• passing the ions extracted through the second aperture through aligned apertures in additional acceleration and focusing electrodes.