Negative-ion sources for modification of materials

The properties of negative ions, such as charging-free ion implantation and new materials syntheses by pure kinetic bonding reaction, have been shown to be promising in terms of their interaction with material surfaces. However, high-current or high-brightness negative-ion sources are required for these purposes. Several kinds of sputter-type negative-ion sources have been developed for negative-ion implantation and deposition in order to obtain high-current heavy negative ions. Recently, a microwave discharge oxygen negative-ion source for negative-ion beam deposition and a surface plasma type hydrogen negative-ion source for projection ion-beam lithography have been investigated. In this article, these negative-ion sources for modification of materials are reviewed. (C) 1996 American Institute of Physics.