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

Paper TF-MoM10
SiO@sub 2@ Atomic Layer Deposition Using HSi[N(CH@sub 3@)@sub 2@]@sub 3@ and H@sub 2@O@sub 2@

Monday, November 15, 2004, 11:20 am, Room 303C

Session: ALD and Applications
Presenter: B.B. Burton, University of Colorado
Authors: B.B. Burton, University of Colorado
S.W. Kang, Pohang University of Science and Technology, Korea
S.M. George, University of Colorado
Correspondent: Click to Email
The atomic layer deposition (ALD) of SiO@sub 2@ has proven to be challenging. SiO@sub 2@ ALD can be accomplished using SiCl@sub 4@ and H@sub 2@O reactants at 600-800 K with large exposures of ~10@super 9@ L. Catalytic SiO@sub 2@ ALD is also achieved at room temperature with the same reactants but requires the presence of a Lewis base catalyst. Recently, we have observed efficient SiO@sub 2@ ALD with HSi[N(CH@sub 3@)@sub 2@]@sub 3@ and H@sub 2@O@sub 2@ reactant exposures. HSi[N(CH@sub 3@)@sub 2@]@sub 3@ is tris-dimethylaminosilane (Tris-DMAS). SiO@sub 2@ ALD was monitored on high surface area ZrO@sub 2@ particles that allowed the use of Fourier transform infrared (FTIR) spectroscopy to monitor the surface chemistry. Following the H@sub 2@O@sub 2@ exposures, the surface displayed vibrational modes consistent with SiOH* species. Tris-DMAS exposure at 825 K converted these species to Si-N(CH@sub 3@)@sub 2@* species and SiH* species. The subsequent H@sub 2@O@sub 2@ exposure converted these species back to SiOH* species. The exposures required for Tris-DMAS and H@sub 2@O@sub 2@ were ~10@super 6@L and ~10@super 7@L, respectively. These exposures are much more favorable than the ~10@super 9@ L exposures required to grow SiO@sub 2@ ALD films with SiCl@sub 4@ and H@sub 2@O at 600-800 K. Other advantages of using Tris-DMAS are the avoidance of HCl as a byproduct and the elimination of possible chlorine contamination in the SiO@sub 2@ film. The SiO@sub 2@ thin films were deposited at temperatures ranging from 525-825 K. The maximum growth rate of 1.9 Å/cycle at 825 K was determined by measuring the SiO@sub 2@ film thickness on ZrO@sub 2@ particles by transmission electron microscopy (TEM). When the temperature was decreased below 825 K, residual SiH* species were observed in the film and led to a decrease in the SiO@sub 2@ ALD growth rate. SiO@sub 2@ growth was also confirmed by the increase in absorbance from the Si-O-Si asymmetric stretch measured by FTIR spectroscopy.