AVS 52nd International Symposium
    Electronic Materials and Processing Monday Sessions
       Session EM-MoA

Paper EM-MoA7
LPCVD of Thin TiO@sub 2@ Films using TDEAT as Ti Source Gas and NH@sub 3@ as a Catalyst

Monday, October 31, 2005, 4:00 pm, Room 309

Session: High-k Dielectric Growth and Processing
Presenter: X. Song, University of Illinois at Chicago
Authors: X. Song, University of Illinois at Chicago
C.G. Takoudis, University of Illinois at Chicago
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Thin TiO@sub 2@ films were deposited using Tetrakis(diethylamino)titanium (TDEAT) and O@sub 2@ as source gases, and NH@sub 3@ as a catalyst. The deposition temperature was 100 - 250°C and the system pressure was on the order of 1 torr. Real-time reactor gas analysis was carried out with a Residual Gas Analyzer. The TiO@sub 2@ film thickness was probed using spectroellipsometry. Time of flight secondary ion mass spectroscopy (ToF-SIMS) was utilized to study the depth profile of oxygen and other elements in the deposited films. The bonding states and atomic compositions of the samples were analyzed with x-ray photoelectron spectroscopy (XPS). It is found that when the TDEAT feed flow rate increases, the TiO@sub 2@ deposition rate increases. The growth rate of TiO@sub 2@ films deposited using NH3 is substantially higher than that of films deposited without NH@sub 3@; for example, at 200°C, the growth rate increases from 4.7 nm/min (without NH@sub 3@) to 38 nm/min (in the presence of NH@sub 3@). XPS data show that the as-deposited Titanium Oxide films are stoichiometric, even when NH@sub 3@ is used. ToF-SIMS depth profile analysis of as-deposited and annealed TiO@sub 2@ is done using Cesium primary ion beam sputtering. The annealing is performed in Oxygen, at 750°C for 10 min. The Oxygen distribution profiles along the depth of both as-deposited and annealed films are found to be uniform; this indicates that Oxygen is incorporated during deposition rather than diffusion during annealing. The impurity levels of C, H, and N are found to be lower in the annealed films than those in the as-deposited films. This study shows that TiO@sub 2@ can be deposited at low substrate temperature and high deposition rates with low impurity levels using TDEAT and O@sub 2@ as source gases and NH@sub 3@ as a catalyst. The impurities in the films can be further reduced with post annealing if desired.