AVS 53rd International Symposium
    Thin Film Tuesday Sessions
       Session TF-TuP

Paper TF-TuP23
Film Improvement of ALD TaN Layers by Application of Additional Energy

Tuesday, November 14, 2006, 6:00 pm, Room 3rd Floor Lobby

Session: Thin Film Poster Session
Presenter: D. Schmidt, Technische Universitaet Dresden, Germany
Authors: D. Schmidt, Technische Universitaet Dresden, Germany
C. Hossbach, Technische Universitaet Dresden, Germany
M. Albert, Technische Universitaet Dresden, Germany
S. Menzel, Leibnitz Institute for Solide State and Materials Research Dresden, Germany
J.-W. Bartha, Technische Universitaet Dresden, Germany
Correspondent: Click to Email
TaN is extensively used as diffusion barrier in copper interconnects and might be considered as deep-trench electrode material. These applications require specific material properties; such as low resistivity, high density, low concentration of impurity, in conjunction with the high uniformity inherent to ALD processes. The self-saturating chemical reactions between the gaseous precursor molecules and the solid surface, favour the Atomic Layer Deposition as an excellent method for depositing highly precise and conformal coatings. Tantalum Nitride thin films have been deposited and studied by using tertiarybutylimidotris(diethylamido)tantalum (TBTDET) as organometallic precursor and ammonia as reducing agent in a conventional ALD. The resulting films show a low density of 8g/cm@super 3@ and a high resistivity of more than 1e+05µ@ohm@-cm. In comparison we studied methods which supply additional energy for the formation of the film. This includes plasma enhancement of the process (direct as well as remote) or thermal post processing (w/o gas environment). We could show that films deposited with PEALD feature a better conductivity of 1e+03µ@ohm@-cm, however several problems are associated with this technique. An alternative plasma enhancement technique, the remote-plasma-assisted ALD (RPALD) is under investigation. By the application of a post process anneal without breaking the vacuum, we could achieve an improvement in film density up to 10,8g/cm@super 3@, in resistivity down to 1e+03µ@ohm@-cm and a reduction of the oxygen content of 50%. The impact of the specific deposition conditions as well as additional procedures on film properties are characterized with in Situ metrology like Ellipsometry and Quartz Crystal Microbalance and of course remote analytic techniques including Atomic Force Microscopy, X-ray Photon Spectroscopy, X-ray Reflectivity/Diffraction and Transition Electron Microscopy.