Jpn. J. Appl. Phys. 41 (2002) pp. 800-804  |Next Article|  |Table of Contents|
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Measurements of the Depth Profile of the Refractive Indices in Oxide Films on SiC by Spectroscopic Ellipsometry

Takeshi Iida, Yuichi Tomioka, Kazuo Yoshimoto, Masahiko Midorikawa, Hiroyuki Tukada, Misao Orihara, Yasuto Hijikata, Hiroyuki Yaguchi, Masahito Yoshikawa¹, Hisayoshi Itoh¹, Yuuki Ishida² and Sadafumi Yoshida

(Received August 8, 2001; accepted for publication November 5, 2001)

The depth profiles of the refractive indices in thermally oxidized films on SiC have been measured by spectroscopic ellipsometry. Oxide films etched at an angle were used to obtain the depth profiles of the refractive indices in the oxide films. The apparent refractive indices n_app and thicknesses have been evaluated, assuming that the films have optically uniform single layer structures. The experimental results show that the values of n_app increase with oxide film thickness, and approach the values for oxide films on Si at around 60 nm in thickness. This feature is almost the same as the changes of refractive indices of oxide films with oxidation time reported previously. These results reveal that the oxide films are not optically uniform and that the optical properties change with depth from the surface. It has been found that the film structure model where the oxide film is composed of two layers, a thin interface layer around 1 nm in thickness with a higher refractive index than those of SiC and SiO₂ and a stoichiometric SiO₂ layer, the thickness of which changes with film thickness, can explain the thickness dependence of n_app observed. These results suggest that there exists an interface layer with high refractive indices at oxide film/SiC interfaces.

KEYWORDS: spectroscopic ellipsometry, 6H-SiC, refractive indices, oxide films, SiC/SiO₂ interface
URL: http://jjap.ipap.jp/link?JJAP/41/800/
DOI: 10.1143/JJAP.41.800

References | Citing Articles (6)

1. S. Yoshida: Electric Refractory Materials, ed. Y. Kumashiro (Marcel Dekker, New York, 2000) p. 437.
2. V. V. Afanas'ev, M. Bassler, G. Pensl and M. Schultz: Phys. Status Solidi A 162 (1997) 312.
3. L. A. Lipkin and J. W. Palmour: J. Electron. Mater. 25 (1996) 909.
4. D. Alok, P. K. McLarty and B. J. Baliga: Appl. Phys. Lett. 64 (1994) 2845[AIP Scitation].
5. M. Yoshikawa, K. Saitoh, T. Ohshima, H. Itoh, I. Nashiyama, Y. Takahashi, K. Ohnishi, H. Okumura and S. Yoshida: Mater. Sci. Forum 264–268 (1998) 1017.
6. W. Cho, R. Kosugi, K. Fukuda, K. Arai and S. Suzuki: Appl. Phys. Lett. 77 (2000) 1215[AIP Scitation].
7. W. Cho, R. Kosugi, K. Fukuda, S. Suzuki and K. Arai: Appl. Phys. Lett. 77 (2000) 2054[AIP Scitation].
8. H. Tsuchida, I. Kamata and K. Izumi: Jpn. J. Appl. Phys. 34 (1995) 6003[IPAP].
9. V. M. Bemudze: J. Appl. Phys. 66 (1989) 6084[AIP Scitation].
10. C. Onneby and C. G. Pantano: J. Vac. Sci. & Technol. A 15 (1997) 1597[AIP Scitation].
11. G. G. Jernigan, R. E. Stahlbush and N. S. Saks: Appl. Phys. Lett. 77 (2000) 1437[AIP Scitation].
12. T. Iida, Y. Tomioka, Y. Hijikata, H. Yaguchi, M. Yoshikawa, Y. Ishida, H. Okumura and S. Yoshida: Jpn. J. Appl. Phys. 39 (2000) L1054[IPAP].
13. M. Yoshikawa, K. Saitoh, T. Ohshima, H. Itoh, I. Nashiyama, S. Yoshida, H. Okumura, Y. Takahashi and K. Ohnishi: J. Appl. Phys. 80 (1996) 282[AIP Scitation].
14. K. J. Hebert, S. Zafar, E. A. lrene, R. Kuehn, T. E. McCarthy and E. K. Demirlioglu: Appl. Phys. Lett. 68 (1996) 266[AIP Scitation].
15. K. J. Hebert, T. Labayen and E. A. Irene: Proc. Electrochem. Soc. 96-1 (1996) 81.
16. T. A. Anastasio: J. Appl. Phys. 38 (1967) 606[AIP Scitation].