High energy implantation: Present and future facilities

Abstract

Accelerators of the tandem type are in common use for high energy ion implantation. The necessary charge exchange at two stages limits the maximum ion current to < 1 mA. A single ended Van de Graaff can deliver ion currents up to 1 mA. The time-consuming opening of the pressurized tank for ion source exchange or service has been avoided in our l MV HVEE accelerator by a high-pressure load lock. This adapted version of the Van de Graaff accelerator is now in use for MeV implantation in semiconductors and metals. Future facilities requiring higher ion energy and more beam current are likely to use rf instead of dc acceleration. After the successful operation of a 115 kV so-called MEQALAC accelerator, a prototype multiple beam 1 MeV rf accelerator is under construction at our Institute. Dc type and different rf accelerators like RFQ, variable phase linac and MEQALAC are compared. MEQALAC is an acronym for a rf linac with electrostatic focusing and with multiple beams.