AVS 51st International Symposium
    Thin Films Monday Sessions
       Session TF-MoM

Paper TF-MoM8
Infrared Analysis of HfO@sub2@ ALD from Hafnium Diethyl-Amide on SiO@sub2@ and Si-H surfaces

Monday, November 15, 2004, 10:40 am, Room 303C

Session: ALD and Applications
Presenter: M.J. Kelly, North Carolina State University
Authors: M.J. Kelly, North Carolina State University
G.N. Parsons, North Carolina State University
J.G. Han, Stanford University
C.B. Musgrave, Stanford University
Correspondent: Click to Email
An important advantage of atomic layer deposition is the potential to control bond structure at the initial growth interface. Deposition of high dielectric constant metal oxides on silicon typically leads to substrate oxidation and uncontrolled interface structure. To explore mechanisms in interface layer growth, we have used attenuated total internal reflection infrared spectroscopy to study of HfO@sub2@ formation on Si-OH and Si-H terminated surfaces from a tetrakis (diethylamido)hafnium metal organic precursor. Precursor exposure at 200°C on the Si-OH surface results show self-limiting chemisorption consistent with formation of Hf-O-Si bonds with substantial Hf-ethylamine ligands remaining. Exposing the surface to H@sub2@O results in removal of C-H modes, consistent with surface oxidation and formation of Hf-OH surface units. Precursor chemisorption is also observed on the Si-H starting surface, likely due to reaction with some surface OH. Distinct changes in the surface Si-H stretching modes are observed upon precursor adsorption, possibly due to interactions between the amine ligands and the surface hydrogen. Exposing this surface to H@sub2@O does not completely oxidize the surface products, consistent with alternate stable surface bonding configurations, likely involving formation of Si-C or Si-N bonds. Ab-initio results describing potential mechanisms of precursor dissociation and Si-H/ligand interactions will be discussed.