Impact of hydrogen plasma treatment on gettering by He implantation-induced cavities in silicon

The use of gettering techniques, with precise location of the gettering regions, has become crucial for device manufacturing. Helium-induced cavities have been shown to getter metallic impurities very effectively, but suffer from the drawback of requiring relatively high He doses. In this work, He-implanted Cz wafers of varying resistivity were subjected to hydrogen plasma hydrogenation prior to the cavity-formation anneal. We focus our studies on the cavity layer interactions with metal impurities. XTEM images reveal that hydrogenation increases the cavity radius. Our SIMS results show that the doping level has no influence on the metal gettering efficiency while the addition of plasma hydrogenation tends to decrease it. However, the efficiency can be controlled with the cavity radius which is interesting for future applications of the technique.