AVS 52nd International Symposium
    Thin Films Wednesday Sessions
       Session TF-WeA

Paper TF-WeA6
ALD-like Deposition of High Quality SiO@sub 2@ Film at 200°C using Organic Silicon Source Gas and Highly Concentrated O@sub 3@ Gas

Wednesday, November 2, 2005, 3:40 pm, Room 306

Session: Fundamentals of Thin Films
Presenter: T. Nishiguchi, Meidensha Corporation, Japan
Authors: T. Nishiguchi, Meidensha Corporation, Japan
N. Kameda, Meidensha Corporation, Japan
Y. Morikawa, Meidensha Corporation, Japan
M. Kekura, Meidensha Corporation, Japan
H. Nonaka, National Institute of Advanced Industrial Science and Technology, Japan
S. Ichimura, National Institute of Advanced Industrial Science and Technology, Japan
Correspondent: Click to Email
One of the technical issues to be solved to fabricate a high performance flexible poly-silicon (p-Si) TFT is the development of the technique of high-quality gate dielectric (SiO@sub2@) film formation even as low as 200 ° C. Although plasma enhanced CVD using an organic silicon source / O@sub 2@ gas is now widely used, the further reduction of impurity incorporation such as carbon and OH is required. Focusing on the high reactivity of O@sub 3@ to organic molecules even at low temperature, we have carried out an ALD-like process by supplying an organic silicon source gas and highly concentrated (100%) ozone (HC-O@sub 3@) gas to a vacuum (< 1 Pa) processing chamber alternately and cyclically. The SiO@sub2@ deposition rate on Si substrate was typically 1 nm per cycle in case of hexamethyldisilazane (HMDS) gas supply of 50 Pa and HC-O@sub3@ gas supply of 1,000 Pa at 200 ° C. As-deposited film was stoichimetric SiO@sub2@ with no Si-CH@sub3@ bond detected by infrared absorption spectroscopy. Leakage current through the film was satisfactory low, i.e. lower than 10@super -7@ A/cm@super 2@ for 3 MV/cm electric field application. However, a film deposited with a higher deposition rate contained a few wt. % Si-OH bonds and H@sub 2@O molecules. We have already confirmed that a UV-light irradiation to Si substrate through an O@sub 3@ atmosphere serves to enhance the chemical reaction at Si surface because of the generation of an excited state oxygen atom in gas phase as well as the temperature rise of uppermost Si region. We are now investigating that the usage of UV irradiation together is effective for achieving both high quality film formation and high deposition rate.