Development a projection ion beam instrument that uses a gas ion source for metal-contamination-free microsampling

Abstract

The authors have developed a metal-contamination-free ion beam instrument with a duoplasmatron that serves as a gas ion source and a projection ion beam optical system that generates a shaped gas ion beam. The luminance of the duoplasmatron ion source is low. However, a projection ion beam optical system can increase the ion current with sharp beam edge profiles enough for microsampling fabrication. A metal-contamination-free shaped gas beam can be used to achieve clean inline sampling and wafer return strategy. The irradiation system of the instrument has three electrostatic lenses, an E × B mass separator, and a mechanism for bending the ion beam to prevent neutral particles from irradiating the samples. The instrument also has a gas flow system for ion beam assisted deposition and a needle transport system for microsampling. Experiments using a prototype implementation demonstrated that microsampling can be achieved by using shaped gas ion beams.