AVS 50th International Symposium
    Surface Science Wednesday Sessions
       Session SS1-WeM

Paper SS1-WeM3
Interface Structure of an Ultrathin SiO@sub 2@ Film Fabricated by Ozone on Si(100)

Wednesday, November 5, 2003, 9:00 am, Room 328

Session: Adsorption on Semiconductor Surfaces
Presenter: K. Nakamura, National Institute of Advanced Industrial Science and Technology (AIST), Japan
Authors: K. Nakamura, National Institute of Advanced Industrial Science and Technology (AIST), Japan
S. Ichimura, National Institute of Advanced Industrial Science and Technology (AIST), Japan
Correspondent: Click to Email
Highly concentrated ozone gas is one of the alternative oxidants to fabricate an ultrathin silicon oxide film at low temperature for the microelectronics technology. Our previous study using an HF etching rate of oxide films has implied that, in contrast to a thermally grown oxide film, the thickness of structural transition layers of an ozone-oxide film is so limited within a much thinner region.@footnote 1@ However, direct information on the structure of this interface has not been so far obtained. Thus, we investigated the structure of an ozone-oxide film at the interface on Si(100) by analyzing transverse optical (TO) and longitudinal optical (LO) phonon modes of Si-O-Si asymmetric stretching vibration with Fourier-transformed infrared spectroscopy (FT-IR). The Si-O-Si bond angle in the ozone-oxide film was found to be undistorted even in the region close to the interface. In the case of a thermally grown oxide film, both peaks are known to make a clear red-shift.@footnote 2,3@ However, the position of a TO phonon peak of an ozone-oxide film fabricated at 350 °C kept constant at 1065 cm@super -1@ within <2 nm thickness. Only the LO phonon peak made a red-shift from 1240 to 1200 cm@super -1@. Since the TO phonon frequency is a function of a Si-O-Si bond angle,@footnote 4@ the result shows that the Si-O-Si angle in the thermally grown oxide is distorted close at the interface, but that this bond angle in the ozone-oxide remains unchanged, thus reducing the thickness of structural transition layers compared to that of the thermal oxide. @FootnoteText@ @footnote 1@ K. Nakamura, S. Ichimura, A. Kurokawa, K. Koike, G. Inoue, and T. Fukuda, 17 (1999) 1275.@footnote 2@ S. Miyazaki, H. Nishimura, M. Fukuda, L. Ley, J. Ristein, Appl. Surf. Sci. 113/114 (1997) 585.@footnote 3@ K. T. Queeney, M. K. Weldon, J. P. Chang, Y. J. Chabal, A. B. Gurevich, J. Sapjeta, and R. L. Opila, J. Appl. Phys. 87 (2000) 1322.@footnote 4@ F. L. Galeener, Phys. Rev. B 19 (1979) 4292.