Abstract

A compact ion and electron beam focusing column design has been developed in Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory. The electrostatic ion beam-focusing column was simulated using 2D IGUN [R. Becker and W. B. Herrmansfeldt, Rev. Sci. Instrum. 63, 2756 (1992)] ion extraction and beam transport code. A new method has been developed to include finite ion temperature to the IGUN simulation (Reijonen et al., Proceedings of the LINAC Conference, 2000). The focused ion beam system includes an ion temperature collimator, which eliminates the large angle beam trajectories resulting in a small beam spot size. The small holes in the column electrodes are laser drilled, and are aligned by an optical comparator. Simulations show that focused beam spot size as small as 147 nm is achievable for a 40 keV argon beam. The compact electron beam focusing system consists of three elements: the plasma cathode, an electron temperature collimator (similar to the ion beam temperature collimator), and the focusing electrode elements. The total length of the system is less than 10 mm. The column design is performed using EGUN (W. B. Herrmansfeldt, Slac Report No. 331, 1988), electron beam computation code, and IGUN. Space charge effects as well as the electron temperature are incorporated in the computation. The simulations show that focused beam spot size of 60 nm can be achieved. Both columns use similar type rf-induction plasma generator. P+, BF2+, and O2+ ion species production by such source is also demonstrated.

Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call