Nucleation Barriers in Chemical Vapor Deposition of Triisobutylaluminum on Silicon
ABSTRACTThe nucleation of chemical vapor deposition (CVD) using triisobutylaluminum (TIBA) on Si (100) surfaces is observed in situ with x-ray photoelectron spectroscopy (XPS). Oxygen from oxide on the silicon inhibits the rate of nucleation by reacting with adsorbed TIBA and forming a thin layer of oxidized organometallic. This layer blocks active adsorption sites and prevents further deposition. On a surface without oxide, the TIBA molecules decompose liberating aluminum that can migrate and nucleate into islands opening sites for further adsorption and film growth. By removing the oxide (native or thermal) in selected areas of the surface, the barrier to nucleation is removed and aluminum deposition can occur in a predetermined pattern.