Germanium performance in the Eaton RF ion source

Abstract

Historically, germanium tetrafluoride (GeF/sub 4/) has been used as a feed material for the creation of beams of Ge ions that are needed for amorphization implants to control channeling effects in source/drain formation. The substitution of germane (GeH/sub 4/) for GeF/sub 4/ is in principle very attractive from a cost of ownership standpoint, since the use of GeF/sub 4/ is known to increase maintenance requirements for conventional high current implanters by reducing the service lifetime of hot cathode ion sources. The safety issues associated with high pressure GeH/sub 4/ have been essentially eliminated through the use of SDS GeH/sub 4/. We present data for SDS GeH/sub 4/ and for high pressure GeF/sub 4/ in the Eaton ULE2, which uses a proprietary RF driven, cold-walled ion source. The performance of the ion source for both feed gas sources of Ge are presented, and compared to results in conventional hot-cathode sources.