DIELECTRIC AND INFRARED PROPERTIES OF ULTRATHIN SiO2 LAYERS ON Si(100)

  • F. GIUSTINO
  • A. PASQUARELLO
Conference paper
Part of the NATO Science Series II: Mathematics, Physics and Chemistry book series (NAII, volume 220)

Abstract

The occurrence of an ultrathin SiO2 oxide layer at the interface between silicon and high-k dielectrics in metal-oxide-semiconductor devices contributes to degrading the capacitance of the gate stack. In this work, we investigate the dielectric and infrared properties of atomically thin SiO2 layers on Si(100) through a fully quantum-mechanical description. For this purpose, we construct atomistic models of the Si(100)-SiO2 interface on the basis of available experimental data, by using both classical and first-principles simulation methods. Our model structures account for the experimental density of coordination defects, the distribution of partially oxidized Si atoms, the oxide mass density profile, and the lateral displacements of the Si atoms in the channel region. Our first principles calculations indicate that the permittivity of the SiO2 layer departs from the bulk value in the limit of atomically thin oxides. This departure is well described through the consideration of an interfacial suboxide layer with a thickness of about 0.5 nm and a dielectric constant of about 6-7. As a consequence, the equivalent oxide thickness of the interfacial layer is smaller than the corresponding physical thickness by 0.2-0.3 nm. Variations of the local dielectric screening occur on length scales corresponding to first-neighbor distances, indicating that the dielectric transition is governed by the chemical grading. We find that the enhanced ionic screening in the substoichiometric oxide results from Si-O bonds formed by Si atoms in the partial oxidation state Si+2. We also extend our investigation to the infrared absorption at the Si(100)-SiO2 interface. Our study allows us to shed light on the pronounced thickness-dependent red shift of the oxygen stretching modes, which has so far not found a definite interpretation. Indeed, our calculations clearly show that the red shift results from a softening of the Si-O stretching vibrations in the interfacial layer.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Awaji, N., Ohkubo, S., Nakanishi, T., Sugita, Y., Takasaki, K., and Komiya, S., 1996, Jpn. J. Appl. Phys. 35(1B):L67–L70.Google Scholar
  2. Bachelet, G. B., Hamann, D. R., and Schlüter, M., 1982, Phys. Rev. B 26(8):4199–4228.CrossRefGoogle Scholar
  3. Bongiorno, A. and Pasquarello, A., 2003, Appl. Phys. Lett. 83(7):1417–1419.CrossRefGoogle Scholar
  4. Bongiorno, A., Pasquarello, A., Hybertsen, M. S., and Feldman, L. C., 2003, Phys. Rev. Lett. 90(18):186101.CrossRefGoogle Scholar
  5. Boyd, I. W. and Wilson, J. I. B., 1987, J. Appl. Phys. 62(8):3195–3200.CrossRefGoogle Scholar
  6. Chang, H. S., Yang, H. D., Hwang, H., Cho, H. M., Lee, H. J., and Moon, D. W., 2002, J. Vac. Sci. Technol. B 20(5):1836–1842.Google Scholar
  7. Devine, R. A. B., 1996, Appl. Phys. Lett. 68(22):3108–3110.CrossRefGoogle Scholar
  8. Dal Corso, A., Baroni, S., and Resta, R., 1994, Phys. Rev. B 49(8):5323–5328.CrossRefGoogle Scholar
  9. Dal Corso, A., Pasquarello, A., Baldereschi, A., and Car, R., 1996, Phys. Rev. B 53(3): 1180–1185.CrossRefGoogle Scholar
  10. Giustino, F., Umari, P. and, Pasquarello A., 2003, Phys. Rev. Lett. 91(26):267601.CrossRefGoogle Scholar
  11. Giustino, F., 2005, Ph.D. thesis, Ecole Polytechnique Fédérale de Lausanne.Google Scholar
  12. Giustino, F. and Pasquarello, A., 2005a, Phys. Rev. B 71(14):144104.CrossRefGoogle Scholar
  13. Giustino, F. and Pasquarello, A., 2005b, Appl. Phys. Lett. 86:192901.CrossRefGoogle Scholar
  14. Giustino, F. and, Pasquarello A., 2005c, Microel. Eng. 80:420–423.Google Scholar
  15. Gonze, X., Allan, D. C., and Teter, M. P., 1992, Phys. Rev. Lett. 68(24):3603–3606.CrossRefGoogle Scholar
  16. Gonze, X., Ghosez, Ph., and Godby, R. W., 1995, Phys. Rev. Lett. 74(20):4035–4038.CrossRefGoogle Scholar
  17. Harris, H., Choi, K., Mehta, N., Chandolu, A., Biswas, N., Kipshidze, G., Nikishin, S., Gangopadhyay, S., and Temkin, H., 2002, Appl. Phys. Lett. 81(6):1065–1067.CrossRefGoogle Scholar
  18. Hirose, K., Kitahara, H., and Hattori, T., 2003, Phys. Rev. B 67(19):195313.Google Scholar
  19. Kirk, C. T., 1988, Phys. Rev. B 38(2):1255–1273.CrossRefMathSciNetGoogle Scholar
  20. Kosowsky, S. D., Pershan, P. S., Krish, K. S., Bevk, J., Green, M. L., Brasen, D., and Feldman, L. C., 1997, Appl Phys. Lett. 70(23):3119–3121.CrossRefGoogle Scholar
  21. Miyazaki, S., Nishimura, H., Fukuda, M., Ley, L., and Ristein, J., 1997, Appl. Surf. Sci. 113/114:585–589.CrossRefGoogle Scholar
  22. Muller, D. A., Sorsch, T., Moccio, S., Baumann, F. H., Evans-Lutterodt, K., and Timp, G., 1999, Nature (London), 399(6738):758–761.CrossRefGoogle Scholar
  23. Muller, D. A. and Wilk, G. D., 2001, Appl. Phys. Lett. 79(25):4195–4197.CrossRefGoogle Scholar
  24. Nakamura, M., Mochizuki, Y., Usami, K., Itoh, Y., and Nozaki, T., 1984, Solid State Commun. 50(12):1079–1081.CrossRefGoogle Scholar
  25. Oh, J. H., Yeom, H. W., Hagimoto, Y., Ono K., Oshima, M., Hirashita, N., Nywa, M., Toriumi, A., and Kakizaki, A., 2001, Phys. Rev. B 63(20):205310.CrossRefGoogle Scholar
  26. Ohwaki, T., Takeda, M., and Takai, Y., 1997, Jpn. J. Appl. Phys. 36(9A):5507–5513.Google Scholar
  27. Pai, P. G., Chao, S. S., Takagi, Y., and Lucovsky, G., 1986, J. Vac. Sci. Technol. A 4(3):689–694.CrossRefGoogle Scholar
  28. Pasquarello, A., Laasonen, K., Car, R., Lee, C., and Vanderbilt, D., 1992, Phys. Rev. Lett. 69(13):1982–1985.CrossRefGoogle Scholar
  29. Pasquarello, A. and Car, R., 1997, Phys. Rev. Lett. 79(9): 1766–1769.CrossRefGoogle Scholar
  30. Pasquarello, A., Hybertsen, M. S., and Car, R., 1998, Nature (London) 396(6706):58–60.CrossRefGoogle Scholar
  31. Perdew, J. P. and Zunger, A., 1981, Phys. Rev. B 23(10):5048–5079.CrossRefGoogle Scholar
  32. Perdew, J. P. and Wang, Y., 1992, Phys. Rev. B 46(20):12947–12954.CrossRefGoogle Scholar
  33. Perkins, C. M., Triplett, B. B., McIntyre, P. C., Saraswat, K. C., Haukka, S., and Tuominen, M., 2001, Appl. Phys. Lett. 78(16):2357–2359.CrossRefGoogle Scholar
  34. Queeney, K. T.,Weldon, M. K., Chang, J. P., Chabal, Y. J., Gurevich, A. B., Sapjeta, J., and Opila, R. L., 2000, J. Appl. Phys. 87(3): 1322–1330.CrossRefGoogle Scholar
  35. Queeney, K. T., Herbots, N., Shaw, J. M., Atluri, V., and Chabal, Y. J., 2004, Appl. Phys. Lett. 84(4):493–495.CrossRefGoogle Scholar
  36. Rochet, F., Poncey, Ch., Dufour, G., Roulet, H., Guillot, C., and Sirotti, F., 1997, J. Non-Crystall. Sol. 216:148–155.Google Scholar
  37. Schumann, L., Lehmann, A., Sobotta, Ff., Riede, V., Teschner, U., and Hübner, K., 1982, Phys. Stat. Sol. B 110(1):K69–K73.Google Scholar
  38. Semiconductor Industry Association, 2003, International Technology Roadmap for Semiconductors, http:llpublic.itrs.net Stesmans, A. and Afanas’ev, V. V., 1998, J. Phys.: Condens. Matter 10(1):L19–L25.Google Scholar
  39. Umari, P. and Pasquarello, A., 2002, Phys. Rev. Lett. 89(15):157602.CrossRefGoogle Scholar
  40. Vanderbilt, D., 1990, Phys. Rev. B 41(11):7892–7895.CrossRefGoogle Scholar
  41. Van Elshocht, S., Caymax, M., De Gendt, S., Conard, T., Petty, J., Daté, L., Pique, D., and Heyns, M. M., 2004, J. Electrochem. Soc. 151:F77.Google Scholar
  42. Vashishta, P., Kalia, R. K., Rinò, J. P., and Ebbsjö, L., 1990, Phys. Rev. B 41(17):12197–12209.CrossRefGoogle Scholar
  43. Wells, J.-P. R., Van Hattum, E. D., Phillips, P. J., Carder, D. A., Habraken, F. H. P. M., and Dijkhuis, J. L., 2004, J. Lumin. 108(1–4):173–176.Google Scholar
  44. Wilk, G. D., Wallace, R. M., and Anthony, J. M., J. Appl. Phys. 89(10):5243–5275.Google Scholar
  45. Witczak, S. C., Suehle, J. S., and Gaitan, M., 1992, Solid-State Electron. 35(3):345–355.CrossRefGoogle Scholar
  46. Yu, P. Y., and Cardona, M., 2003, Fundamentals of Semiconductors: Physics and Materials Properties, 3rd ed., Springer-Verlag, New York, p. 337.Google Scholar

Copyright information

© Springer 2006

Authors and Affiliations

  • F. GIUSTINO
    • 1
  • A. PASQUARELLO
    • 2
  1. 1.Institute of Theoretical PhysicsEcole Polytechnique Fédévrale de Lausanne (EPFL)LausanneSwitzerland
  2. 2.Institut Romand de Recherche Numérique en Physique desMatériaux (IRRMA)LausanneSwitzerland

Personalised recommendations