No Access Submitted: 12 November 1999 Accepted: 17 May 2000 Published Online: 26 July 2000
Journal of Applied Physics 88, 2138 (2000);
more...View Affiliations
  • Plasma Chemistry Center—CNR, via Orabona, 4—70126 Bari, Italy
View Contributors
  • M. Losurdo
  • P. Capezzuto
  • G. Bruno
The interaction of α-Al2O3 (0001) surfaces with H atoms and N atoms from remote rf plasmas used for the cleaning and nitridation processes, respectively, is investigated at temperatures in the range of 200–600 °C. The chemistry and kinetics of the above processes are monitored in real time by in situ spectroscopic ellipsometry. Also, the chemistry of the nitrided sapphire surfaces is verified by x-ray photoelectron spectroscopy (XPS) analysis. Specifically, H atoms treatments are effective in removing carbon contaminants from the sapphire surface at temperatures of 200–400 °C. Real time ellipsometry is suitable to detect the cleaning end point and to verify the onset of the H-atom diffusion into the sapphire substrate. Remote N2 plasma nitridation at 200 °C is found to yield homogeneous and smooth AlN layers of about 5 Å, after approximately 25 min of nitridation, whereas high nitridation temperatures result in a damaged sapphire surface with AlN protrusions. Both ellipsometric and XPS data show that the sapphire nitridation can be interpreted in the framework of a chemical model, where the formation of NO competes with AlN formation. The chemisorption equilibrium of NO, which strongly depends on surface temperature, is the key factor controlling the nitridation chemistry and kinetics.
  1. 1. Y. Golan, P. Fini, S. P. DenBaars, and J. S. Speck, Jpn. J. Appl. Phys., Part 1 37, 4695 (1998). Google ScholarCrossref
  2. 2. C. Heinlein, J. Grepstad, T. Berge, and H. Riechert, Appl. Phys. Lett. 71, 341 (1997). Google ScholarScitation, ISI
  3. 3. P. Vennegues, B. Beaumont, S. Haffouz, M. Vaille, and P. Gibart, J. Cryst. Growth 187, 167 (1998). Google ScholarCrossref
  4. 4. N. Grandjean, J. Massies, and M. Leroux, Appl. Phys. Lett. 69, 2071 (1996). Google ScholarScitation, ISI
  5. 5. K. Uchida, A. Watanabe, F. Yano, M. Kouguchi, T. Tanaka, and S. Minagawa, J. Appl. Phys. 79, 3487 (1996). Google ScholarScitation, ISI
  6. 6. S. Keller, B. P. Keller, Y. F. Wu, B. Heying, D. Kapolnek, J. S. Speck, U. K. Mishra, and S. P. DenBaars, Appl. Phys. Lett. 68, 1525 (1996). Google ScholarScitation, ISI
  7. 7. K. Balakrishnan, H. Okumura, and S. Yoshida, J. Cryst. Growth 189/190, 244 (1998). Google ScholarCrossref, ISI
  8. 8. F. Widmann, G. Feuillet, B. Daudin, and J. L. Rouviere, J. Appl. Phys. 85, 1550 (1999). Google ScholarScitation, ISI
  9. 9. C. Heinlein, J. Grepstad, H. Reichert, and R. Averbeck, Mater. Sci. Eng., B 43, 253 (1997). Google ScholarCrossref
  10. 10. C. Heinlein, J. Grepstad, S. Einfeldt, D. Hommel, T. Berge, and A. P. Grande, J. Appl. Phys. 83, 6023 (1998). Google ScholarScitation, ISI
  11. 11. Y. Cho, Y. Kim, E. R. Weber, S. Rumivov, and Z. L. Weber, J. Appl. Phys. 85, 7909 (1999). Google ScholarScitation, ISI
  12. 12. T. Tokuda, A. Wakahara, S. Noda, and A. Sasaki, J. Cryst. Growth 183, 62 (1998). Google ScholarCrossref
  13. 13. T. D. Moustakas, T. Lei, and R. J. Molnar, Physica B 185, 36 (1993). Google ScholarCrossref, ISI
  14. 14. W. Kim, M. Yeadon, A. E. Botchkarev, S. N. Mohammad, J. M. Gibson, and H. Morkoc, J. Vac. Sci. Technol. B 15, 921 (1997). Google ScholarCrossref, ISI
  15. 15. H. Kawakami, K. Sakurai, K. Tsubouchi, and N. Mikoshiba, Jpn. J. Appl. Phys., Part 2 27, L161 (1988). Google ScholarCrossref, ISI
  16. 16. H. G. Tompkins, A User’s Guide to Ellipsometry (Academic, San Diego, CA, 1993). Google Scholar
  17. 17. A. R. Balkenede, O. L. J. Gijzeman, and J. W. Geus, Appl. Surf. Sci. 37, 189 (1989). Google ScholarCrossref
  18. 18. G. Bruno, M. Losurdo, and P. Capezzuto, J. Vac. Sci. Technol. A 13, 349 (1995). Google ScholarCrossref
  19. 19. M. Losurdo, P. Capezzuto, G. Bruno, and E. A. Irene, Phys. Rev. B 58, 15 878 (1998). Google ScholarCrossref
  20. 20. G. Bruno, M. Losurdo, and P. Capezzuto, Appl. Phys. Lett. 66, 3573 (1995). Google ScholarScitation
  21. 21. E. D. Palik, in Handbook of Optical Constants of Solids II, edited by E. D. Palik (Academic, New York, 1991). Google Scholar
  22. 22. S. Loughin and R. H. French, in Properties of Group III Nitrides, edited by J. H. Edgar (INSPEC, London, 1994), p. 175. Google Scholar
  23. 23. H. Demiryont, L. R. Thompson, and G. J. Collins, Appl. Opt. 25, 1311 (1986). Google ScholarCrossref
  24. 24. D. Brunner, J. Angerer, E. Bustarret, F. Freudenberg, R. Hopler, R. Dimitrov, O. Ambacher, and M. Stutzmann, J. Appl. Phys. 82, 5090 (1997). Google ScholarScitation, ISI
  25. 25. X. Tang, Y. Yuan, K. Wongchotigul, and M. G. Spencer, Appl. Phys. Lett. 70, 3206 (1997). Google ScholarScitation, ISI
  26. 26. T. Wethkamp, K. Wilmers, C. Cobet, N. Esser, W. Richter, O. Ambacher, M. Stutzmann, and M. Cardona, Phys. Rev. B 59, 1845 (1999). Google ScholarCrossref, ISI
  27. 27. D. A. G. Bruggemann, Ann. Phys. (Leipzig) 24, 636 (1935). Google ScholarCrossref
  28. 28. Y. Kamiura, Y. Yamashita, and S. Nakamura, Jpn. J. Appl. Phys., Part 2 37, L970 (1998). Google ScholarCrossref
  29. 29. J. F. Moulder, W. F. Stickle, P. E. Sobol, and K. D. Bomben, in Handbook of X-ray Photoelectron Spectroscopy, edited by J. Chastain (Perkin–Elmer, Eden Prairie, MN, 1992). Google Scholar
  30. 30. R. M. Ormerod, K. L. Peat, W. J. Wytenburg, and R. M. Lambert, Surf. Sci. 269/270, 506 (1992). Google ScholarCrossref
  31. 31. D. Briggs and M. P. Seah, Practical Surface Analysis by Auger and X-ray Photoelectron Spectroscopy (Wiley, New York, 1983), pp. 133, 362. Google Scholar
  32. 32. J. S. Paek, K. K. Kim, J. M. Lee, D. J. Kim, M. S. Yi, D. Y. Noh, H. G. Kim, and S. J. Park, J. Cryst. Growth 200, 55 (1999). Google ScholarCrossref, ISI
  33. 33. M. Losurdo, P. Capezzuto, G. Bruno, P. R. Lefebvre, and E. A. Irene, J. Vac. Sci. Technol. B 16, 2665 (1998). Google ScholarCrossref
  34. 34. M. Losurdo, P. Capezzuto, G. Bruno, G. Leo, and E. A. Irene, J. Vac. Sci. Technol. A 17, 2194 (1999). Google ScholarCrossref
  35. 35. A. D. Loganand G. W. Graham, Surf. Sci. Lett. 277, L47 (1992). Google ScholarCrossref
  36. 36. G. W. Graham, Surf. Sci. 268, 25 (1992). Google ScholarCrossref
  37. 37. P. Guenard, G. Renaud, and A. Barbier, Mater. Res. Soc. Symp. Proc. 437, 15 (1996). Google ScholarCrossref
  38. 38. W. T. Taferner, A. Bensaoula, E. Kim, and A. Bousetta, J. Cryst. Growth 164, 167 (1996). Google ScholarCrossref, ISI
  39. 39. K. Sawabeand Y. Matsumoto, Surf. Sci. 283, 126 (1993). Google ScholarCrossref
  40. 40. S. Sugai, K. Shimizu, H. Watanabe, H. Miki, and K. Kawasaki, Surf. Sci. 287/288, 455 (1993). Google ScholarCrossref
  41. 41. M. Kiskinova, G. Pirug, and H. P. Bonzel, Surf. Sci. 140, 1 (1984). Google ScholarCrossref
  42. 42. F. S. Bao, Z. R. Hong, C. P. Lin, and T. J. Chang, Surf. Sci. Lett. 247, L224 (1991). Google Scholar
  43. 43. H. P. Steinruck, C. Schneider, P. A. Heimann, T. Pache, E. Umbach, and D. Menzel, Surf. Sci. 208, 136 (1989). Google ScholarCrossref
  1. © 2000 American Institute of Physics.