An extremely monoenergetic ion beam by photoionisation of xenon atoms

PI: Chris Foot

Department: Physics

Focused Ion Beam (FIB) machines are ubiquitous for nanofabrication and sample preparation, e.g. as an essential tool for diagnosing faults in new generations of microprocessors. Prof Foot aims to design a source of xenon ions with a very low spread of energies to improve FIB performance. A great advantage of using xenon, a noble gas, is that it does not contaminate the sample with metal, as occurs with industry-standard ion sources using gallium. Prof Foot’s design is an example of a new type of ion source in which precisely controlled laser radiation dissociates atoms with negligible excess energy. His research group has carried out the technically difficult step of photoionisation of xenon (using photons to create xenon ions) in previous work. Ultraviolet radiation at the required wavelength is now available from commercial laser systems (costing much less than high-end FIB machines). First adopters are likely to be companies supplying FIB services to the semiconductor industry.