AVS 45th International Symposium
    Electronic Materials and Processing Division Wednesday Sessions
       Session EM1-WeA

Paper EM1-WeA8
Influence of Rapid Thermal Annealing on Vicinal Si(111)/SiO@sub 2@ Interfaces Investigated by Optical Second Harmonic Generation.

Wednesday, November 4, 1998, 4:20 pm, Room 314/315

Session: Si Surface Chemistry
Presenter: J.F.T. Wang, North Carolina State University
Authors: J.F.T. Wang, North Carolina State University
G.D. Powell, North Carolina State University
D.J. Stephens, North Carolina State University
R.S. Johnson, North Carolina State University
B.R. Solazzo, North Carolina State University
Y. Wu, North Carolina State University
D.E. Aspnes, North Carolina State University
G. Lucovsky, North Carolina State University
Correspondent: Click to Email
We have studied optical Second Harmonic Generation, SHG, from Si/SiO@sub 2@ interfaces formed by 800°C thermal oxidation of vicinal Si(111) surfaces off-cut approximately 5 degrees in the 112bar direction. Changes in the rotational anisotropy of the SHG were observed when interfaces were annealed at temperatures between about 800 and 1000°C. We have analyzed the rotational anisotropy by including harmonic functions that reflect the C@sub 1v@ and C@sub 3v@ symmetry of the vicinal Si(111) surface corresponding respectively to steps and terraces of the vicinal surfaces. The relative phase difference, @phi@@sub 13@, between the C@sub 1v@ and C@sub 3v@ harmonic contributions is strongly influenced by the Rapid Thermal Annealing, RTA, temperature. In this paper we compare our results with an incident wavelength of 800 nm (or 1.55 eV) from a Ti:sapphire laser to previous reported work with incident wavelength of 1053 nm (or 1.17eV) using a Nd:YLF laser. The largest change in @delta@@phi@@sub 13@, ~72 degrees, using the 1.55 eV laser source is between 800°C and 900°C which is consistent with the previously reported studies using the Nd:YLF laser.@footnote 1@ However, @delta@@phi@@sub 13@ is larger for a pump beam of 800 nm compared to that of 1053 nm, ~72° compared to ~38°. These results are consistent with the anharmonic oscillator model if the laser energy is less than about one-half of the resonance energy of the anharmonic oscillator.@footnote 2@ Finally, it is important to note that annealing at 900°C has been shown to reduce sub-oxide interfacial bonding introduced at the Si/SiO@sub 2@ interface during thermal and plasma-assisted oxidation processes@footnote 3@ suggesting that changes in @delta@@phi@@sub 13@ between 800 and 900°C anneals in the SHG response are associated with changes in interface bonding that include a reduction of the extent of transition regions with the sub-oxide bonding arrangements. @FootnoteText@ @footnote 1@C. H. Bjorkman, C. E. Shearon, Jr., Y. Ma, T. Yasuda, G. Lucovsky, U. Emmerichs, C. Meyer, K. Leo, and H. Kurz, J. Vac. Sci. Technol. A11(4), 964 (1993) @footnote 2@Y. R. Shen, The Principles of Nonlinear Optics (John Willey & Sons, New York, 1984) @footnote 3@G. Lucovsky, A. Banerjee, B. Hinds, C. Claflin, K. Koh and H. Yang, J. Vac. Sci. Technol. B15, 1074 (1997), and references therein.