0035-001X

S0035-001X2008000300005

México

00 06 2008

54 3 200 207

Investigación

A low–temperature and seedless method for producing hydrogen–free Si₃N₄

A.L. Leal–Cruz, M.I. Pech–Canul*, and J.L. de la Peña

Centro de Investigación y de Estudios Avanzados del IPN–Unidad Saltillo, Carr. Saltillo–Monterrey Km. 13. Saltillo, 25900 Coahuila, México.

* Corresponding author:
Phone: +52 (844) 438–9600 Ext. 9678. Fax: 438–9610, ]]> e–mail: martin.pech@cinvestav.edu.mx, martin_pech@yahoo.com.mx

Recibido el 17 de septiembre de 2007
Aceptado el 3 de abril de 2008

Abstract

A simple, seedless method for the synthesis of Si₃N₄ from a hydrogen–free precursor system (Na₂SiF_6(s)–N_2(g)) was developed. From thermodynamic calculations and experimental results it is concluded that the gaseous chemical species SiF_x (SiF₄,SiF₃, SiF₂, SiF and Si) formed during the low–temperature dissociation of Na₂SiF₆ in a conventional CVD system react in–situ with nitrogen to produce Si₃N₄. Whiskers, fibers, coatings and powders were obtained via the Na₂SiF₆–N₂ system at pressures slightly above atmospheric pressure. Not only does the feasibility of the reactions for Na₂SiF₆ dissociation and Si₃N₄ formation increase with the temperature but also, once the SiF_x chemical species are formed by the former, the latter reaction is even more viable. Amorphous Si₃N₄ is obtained at temperatures of up to 1173 K while crystalline α– and β–Si₃N₄ are formed in the range 1273–1573 K and with processing times as short as 120 minutes. Optimal conditions for maximizing Si3N4formation were determined.

Keywords: Thermodynamics; CVD; Amorphous Si₃N₄; α– and β–Si₃N₄; gas–solid precursors.

Resumen

]]> Se desarrolló un método simple y sin semillas para la síntesis de Si₃N₄ partiendo de un sistema de precursores libre de hidrógeno (Na₂SiF_6(s)–N_2(g)). A partir de cálculos termodinámicos y resultados experimentales se concluye que las especies químicas gaseosas SiF_x (SiF₄,SiF₃, SiF₂, SiF and Si) formadas durante la disociación a baja temperatura del Na₂SiF₆ en un sistema convencional de CVD reaccionan in situ con el nitrogeno para producir Si₃N₄. Se obtuvieron fibras, fibras cortas discontinuas, recubrimientos y polvos a través del sistema Na₂SiF₆_(s)–N₂ a presiones ligeramente por encima de la presión atmosférica. Con el incremento en la temperatura no solo aumenta la factibilidad de las reacciones para la disociación del Na₂SiF₆ y formación del Si₃N₄, sino también una vez que se han formado las especies SiF_x por la primera reacción, la segunda reacción es incluso más factible. El Si₃N₄ amorfo se obtiene a temperaturas de hasta 1173 K mientras que el Si₃N₄ cristalino α y β se forman en el rango de temperaturas de 1273–1573 K y con tiempos de procesamiento tan cortos como 120 minutos. Se determinaron las condiciones óptimas para maximizar la formación del Si₃N₄.

Descriptores: Termodinámica; CVD; Si₃N₄amorfo; Si₃N₄α y β; precursores gas–sólido.

PACS: 81.15.Gh; 81.20.Ka; 82.60.–s

DESCARGAR ARTÍCULO EN FORMATO PDF

Acknowledgements

Authors express their gratitude to Conacyt (National council of Science and Technology, México) for financial support under project No. CB–2005–1/24322. Dr. Leal–Cruz gratefully acknowledges Conacyt's assistance in providing a doctoral scholarship. Authors also wish to thank Mr. Felipe Marquez Torres for technical assistance during the characterization by scanning electron microscopy (SEM).

]]> Referencias

1. F. Galasso, U. Kuntz, and W.J. Croft, J. Am. Ceram. Soc. 55 [8] (1972) 431. [ Links ]

2. K.S. Mazdiyasni and C.M. Cooke, J.A. Ceram, Soc. 56 [12] (1973) 628. [ Links ]

3. K. Hajime, S. Shinichi, and I. Takao, [ Links ] Japan Patent No. JP58115008 (1983).

4. W.–C. Lee and S.–L. Chung, J. of Materials Research 12 [3] (1997) 805. [ Links ]

5. K. Tang et al., Advanced Materials 11 [8] (1999) 653. [ Links ]

6. A. de Pablos, J. Bermuda, and M.I. Osendi, J. Am. Ceram. Soc. 84 [5] (2001) 1033. [ Links ]

7. Y.G. Cao et al., J. of Crystal Growth 234 (2002) 9. [ Links ]

8. C. Dianying, Z. Baolin, Z. Hanrui, L. Wenlan, and X. Suying, Materials Research Bulletin 37 | (2002) 1481. [ Links ]

9. H. Arik, J. of the Eur. Cer. Soc. 23 (2003) 2005. [ Links ]

10. Y. Gu, L. Chen, and Y. Qian, J. Am. Ceram. Soc. 87 [9] (2004) 1810. [ Links ]

11. I.G. Cano and M.A. Rodríguez, Scripta Materialia 50 (2004) 383. [ Links ]

12. A.L. Leal–Cruz and M.I. Pech–Canul, Mater. Chem. and Phys. 98 (2006) 27. [ Links ]

13. R.C.G. Swann, R.R. Mehta, and T.P Cauge, J. Electrochem. Soc.: Solid State Science. 114 [7] (1967) 713. [ Links ]

14. E.A. Taft, J. Electrochem. Soc. 118 [8] (1971) 1341. [ Links ]

15. A.K. Sinha, H.J. Levinstein, T.E. Smith, G. Quintana, and S. E. Haszko, J. Electrochem. Soc.: Solid–State Science and Technology 125 [4] (1973) 601. [ Links ]

16. A.K. Sinha and T.E. Smith, J. Appl. Phys. 49 [5] (1978) 2756. [ Links ]

17. H. Nakayama and T. Enomoto, Japanese J. of Appl. Phys. 18 [9] (1979) 1773. [ Links ]

18. S. Fujita, M. Nishihara, W–L Hoi, and A. Sasaki, Japanese J. of Appl. Phys. 20 [5] (1981) 917. [ Links ]

19. M. Maeada and Y. Arita, J. Appl. Phys. 53 [10] (1982) 6852. [ Links ]

20. A.J. Lowe, M.J. Powell, and S.R. Elliot, J. Appl. Phys. 59 [4] (1986) 1251. [ Links ]

21. Y Manabe and T. Mitsuyu, J. Appl. Phys. 66 [6] (1989) 2475. [ Links ]

22. R.K. Pandey, L.S. Patil, J.P. Bange, and D.K. Gautam, Optical Materials 27 (2004) 139. [ Links ]

23. W.E. Lee and W.M. Rainforth, Ceramic microstructures, property control by processing (Chapman & Hall, New York, 1994). [ Links ]

24. K.L. Choy, Progress in Materials Science 48 (2003) 57. [ Links ]

25. R.C. Weast, C.R.C. Handbook of Chemistry and Physics, 51 ed. (The Chemical Rubber Co., Cleveland OH, 1970). [ Links ]

26. F.S. Galasso, R.D. Veltri, and W.J. Croft, Am. Ceram. Soc. Bull. 57 [4] (1978) 453. [ Links ]

27. M. Vanka and J. Vachuska, Termochimica Acta 36 (1980) 387. [ Links ]

28. P. Chiotti, Journal of Less–Common Metals 80 (1981) 105. [ Links ]

29. Y Kashiwaya and A.W. Cramb, Metall. and Mater. Trans. 33B (2002) 129. [ Links ]

30. A.L. Leal–Cruz and M.I. Pech–Canul, J. Solid State Ionics 177 (2007) 3529. [ Links ]

31. R. Roy, A Primer on the Taguchi Method, Society of Manufacturing Engineers (Dearborn Michigan, 1990). [ Links ]

32. F.S. Galasso, R.D. Veltri, and W.J. Croft, J. Amer. Ceram. Soc. 57 [4] (1978) 453. [ Links ]

33. J.D. Wu et al.,Thin Solid Films 350 (1999) 101. [ Links ]

34. M. Vila, C. Prieto, P. Miranzo, M.I. Osendi, and R. Ramírez, Surface and Coatings Tech. 151–152 (2002) 67. [ Links ]

35. R.K. Pandey, L.S. Patil, Jaspal P. Bange, D.K., J. Optical Materials 27 (2004) 139. [ Links ]

36. B.S. Sahu, P. Srivastava, O.P. Agnihotri, and S.M. Shivaprasad, J. of non–crystalline solids 351 (2005) 771. [ Links ]

37. J.D. McDonald, C.H. Williams, J.C. Thompson, and J.L. Margrave, Advan. Chem. Ser. 72 (1968) 261. [ Links ] ]]> 1 1972 55 8 8 431 2 1973 56 12 12 628 3 4 1997 12 3 3 805 5 1999 11 8 8 653 6 2001 84 5 5 1033 7 2002 234 234 9 8 2002 37 37 1481 9 2003 23 23 2005 10 2004 87 9 9 1810 11 2004 50 50 383 12 2006 98 98 27 13 1967 114 7 7 713 14 1971 118 8 8 1341 15 1973 125 4 4 601 16 1978 49 5 5 2756 17 1979 18 9 9 1773 18 1981 20 5 5 917 19 1982 53 10 10 6852 20 1986 59 4 4 1251 21 1989 66 6 6 2475 22 2004 27 27 139 23 1994 24 2003 48 48 57 25 1970 51 26 1978 57 4 4 453 27 1980 36 36 387 28 1981 80 80 105 29 2002 33B 33B 129 30 2007 177 177 3529 31 1990 32 1978 57 4 4 453 33 1999 350 350 101 34 2002 151-152 151-152 67 35 2004 27 27 139 36 2005 351 351 771 37 1968 72 72 261