Ge+ ion extraction from a microwave ion source

Abstract

Preamorphization of a silicon substrate by Ge+ ion implantation is required for shallow doping of boron, which, in turn, is the key process to realize highly integrated semiconductor devices. However, Ge+ ions have not been stably extracted by conventional methods. Several chemical compounds of germanium, GeO, GeS, GeCl4, and GeF4, were supplied to a microwave ion source and the characteristics of their ion extractions were compared. The conditions for obtaining mass-separated Ge+ ions of more than 1 mA were found.