AVS 52nd International Symposium
    Thin Films Tuesday Sessions
       Session TF-TuM

Paper TF-TuM1
Atomic Layer Deposition of Titanium Oxide Thin Films using O@sub 3@ for MIM Capacitor of Next Generation Memory Devices

Tuesday, November 1, 2005, 8:20 am, Room 306

Session: Atomic Layer Deposition - Oxides
Presenter: S.K. Kim, Seoul National University, Korea
Authors: S.K. Kim, Seoul National University, Korea
K.M. Kim, Seoul National University, Korea
C.S. Hwang, Seoul National University, Korea
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TiO@sub 2@ films were deposited using a travelling-wave type ALD reactor on a bare-Si (100) wafer, sputtered and ALD Ru, and sputtered Pt electrodes at a wafer temperature of 250°C. TiO@sub 2@ thin films was grown using Ti(OC@sub 3@H@sub 7@)@sub 4@ and O@sub 3@ as the precursor and oxidant, respectively. The dielectric constants of these TiO@sub 2@ films are 83 between 100 for the films on Ru electrodes. Crystalline structure of TiO@sub 2@ films on various substrates was investigated to understand the origin of higher k values of TiO@sub 2@ films on Ru substrates. XRD results of TiO@sub 2@ films on various substrates show that the TiO@sub 2@ films on Si and Pt substrates have anatase structure whereas the films on Ru substrates have rutile phase grains. This means that the growth of rutile TiO@sub 2@ is related to the kind of substrate. The growth of rutile TiO@sub 2@ on Ru substrate is induced by the formation of RuO@sub 2@, which has almost identical ion arrangements in its rutile structure, at the TiO@sub 2@/Ru interface. For the application of the material and ALD process to DRAM devices, TiO@sub 2@ films were grown on contact hole structured Ru electrodes and the dielectric properties of Ru/TiO@sub 2@/Ru 3-D capacitor were investigated. The conformity in film thickness and dielectric properties over the entire structured surface was confirmed by capacitance variation vs. hole surface area experiments. Also, addition of Al as an acceptor in TiO@sub 2@ films was tried to improve the leakage properties of TiO@sub 2@ films due to a rather high leakage current density of TiO@sub 2@ films. Although toxeq. of doped-TiO@sub 2@ films is smaller than that of undoped-TiO@sub 2@ films, leakage current density of doped-TiO@sub 2@ films is much lower than that of undoped-TiO@sub 2@ films.