Analysis by Surface-sensitive Second Harmonic Generation of Si(111)7×7 Exposed to High-purity Ozone Jet for Oxide Film Formation
✍ Scribed by Nakamura, Ken; Kurokawa, Akira; Ichimura, Shingo
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 354 KB
- Volume
- 25
- Category
- Article
- ISSN
- 0142-2421
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✦ Synopsis
We observed an in situ process of ozone adsorption on Si(111)7 Â 7 at di †erent temperatures by second harmonic generation (SHG). On ozone exposure, the second harmonics (SH) intensity descreased close to a detectable limit on the surface at room temperature (RT). However, we observed the appearance of another SH intensity during ozone exposure at elevated substrate temperatures between 260 ÄC and 400 ÄC, after it decreased in the same way as that at RT. On these surfaces, the proÐle of SH intensity recovery by desorption of adsorbed species indicated that di †erent adsorbed species were formed during surface exposure to ozone at di †erent substrate temperatures : those at RT are weakly adsorbed species for termination of dangling bonds and insertion into backbonds, and those at higher temperatures have an Si-O-Si network which is more stable and desorbs at higher temperatures than 700 ÄC. We conclude that the SH intensity that appeared on the surfaces at elevated temperatures is due to more stable Si-O-Si bonding as an initial step of oxide formation. 1997 by John Wiley & Sons, Ltd. SiO 2 -like