An ion implantation apparatus and method are disclosed for reducing contamination of doubly-charged ions by singly-charged ions. A liner, with a grooved or smooth surface, formed of beryllium or graphite reduces secondary electron scattering into the ion beam. Solid red phosphorus reduces the operating...http://www.google.de/patents/US4560879?utm_source=gb-gplus-sharePatent US4560879 - Method and apparatus for implantation of doubly-charged ions
