Metal oxide cross contamination in ion implanters

Tunneling current and boron penetration increase dramatically as conventional silicon dioxide gate dielectric films are scaled below 1.5 nm in thickness. Because of these effects, the International Technology Roadmap for Semiconductors predicts the introduction of new gate dielectric materials within the next few years. High dielectric constant materials based on metallic oxides of Zirconium, Hafnium, and other transition metals have been proposed as candidate gate dielectric materials. The introduction of metallic oxides leads to concerns about metallic contamination in the processing tools. Ion implant tools are of particular concern since the nature of the implantation process is likely to sputter the exposed metallic oxides and can cause cross contamination to other wafers. Experiments have been performed to quantify the potential for metallic contamination from metallic oxides.