The Impact of Carbon on the Warpage of e-SiGe Wafers During Laser Anneal

When wafers with embedded SiGe (e-SiGe) are laser annealed, serious wafer warpage can result. This warpage will lead to registration error when patterning is attempted to create contacts, and can make subsequent processing of the wafers impossible. If relatively low levels of carbon are introduced into the SiGe prior to laser anneal, wafer warpage is reduced. Carbon can be introduced through implantation or by co-deposition during the epitaxial growth of the SiGe. This paper illustrates the impact that laser anneal has on e-SiGe wafers, and explores the impact of carbon on these effects. Mechanisms by which carbon influences warpage are discussed, and the manufacturing impact of this introduction is reviewed. Finally, species other than carbon are examined for their ability to modify wafer warpage in laser annealed e-SiGe wafers.