AVS 50th International Symposium
    Thin Films Monday Sessions
       Session TF-MoA

Paper TF-MoA3
Copper Atomic Layer Deposition Using In Situ-Generated Cu@sub 3@Cl@sub 3@ and Hydrogen Radicals

Monday, November 3, 2003, 2:40 pm, Room 329

Session: Atomic Layer Deposition and Low-k
Presenter: M.D. Groner, University of Colorado
Authors: M.D. Groner, University of Colorado
S.M. George, University of Colorado
Correspondent: Click to Email
Copper (Cu) atomic layer deposition (ALD) has been achieved using in situ-generated Cu@sub3@Cl@sub3@ and hydrogen radicals. The Cu ALD chemistry involves copper chloride adsorption on the substrate followed by copper chloride reduction to copper metal using hydrogen radicals. The copper chloride precursor, Cu@sub3@Cl@sub3@, is generated in situ when a small Cl@sub2@ or SnCl@sub4@ gas pulse transported by a carrier gas contacts a high surface area Cu braid at T> 200 °C. The in-situ generation of Cu@sub3@Cl@sub3@ overcomes the stability problems associated with using a heated CuCl source to generate the copper chloride. The Cu ALD is performed using a "moving sample" reactor in which a pneumatic transfer arm shuttles the sample between the Cu@sub3@Cl@sub3@ dosing region and the inductively coupled plasma (ICP) hydrogen radical source. This reactor design is important because close proximity to the hydrogen radical source is necessary to overcome efficient hydrogen radical recombination on the reactor walls. Cu ALD films have been grown on glass, sapphire, and silicon substrates. The Cu ALD films nucleate well on the various substrates after hydrogen radical exposures. Cu ALD growth rates of >1 Å/cycle have been achieved as determined by real-time in situ optical thickness measurements of the Cu film growth. The Cu films are very shiny and copper-colored and display a high reflectivity. X-ray diffraction (XRD) analysis of the Cu films show distinct (111), (200), (220) and (311) diffraction peaks with no additional XRD peaks. Preliminary studies have shown successful Cu ALD at substrate temperatures ranging from ~200-260 °C. Further results will be presented on the dependence of growth temperature, copper chloride precursor exposure and hydrogen radical exposure.