Characterization of phosphonate terminated polyethylene glycol on Si (111) wafers

CHED 304

Raymond K. Bogdon, dstallings@georgiasouthern.edu, James S. Burgess, and Dontarie M. Stallings. Department of Chemistry, Georgia Southern University, Post Office Box 8064, Stateboro, GA 30460
Research was performed on the coating of silicon wafers with biologically active molecules. The wafers were cleaned and a hydroxyl layer was formed on the surface using UV/ozone and adsorbed water. The wafer was then reacted with ammonium fluoride to form a hydrogen layer on the surface. A vacuum system was designed and built to react the wafers with chlorine at 5 mTorr of pressure. The chlorinated surface was then exposed to polyethylene glycols (PEGs) with varying chain lengths. These formed well-ordered structures on the surface. The PEG was then activated by way of phosphonate termination. The surfaces were characterized by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and ellipsometry.