Segregation Gettering Model for Nickel in p/p+ Silicon Wafers

Abstract

The segregation gettering of nickel in p/p+ silicon epitaxial wafers is analyzed based on the gettering model considering the competitive interaction between segregation effect and nickel precipitations at the surface during the cooling process after heat treatments. It is found that the segregation is effective at higher temperatures than Ni-silicide formation temperatures even if the nickel donor level lies close to the valence band edge, resulting in the suppression of Ni-silicide formation at lower temperatures. The gettering effect is suggested to be useful for the low temperature process for a future device fabrication.