Metallization strategies for In2O3-based amorphous oxide semiconductor materials

Abstract

Amorphous oxide semiconductors based on indium oxide [e.g., In–Zn–O (IZO) and In–Ga–Zn–O (IGZO)] are of interest for use in thin-film transistor (TFT) applications. We report that the stability of amorphous In–Zn–O (a-IZO) used in TFT applications depends, in part, on the metallization materials used to form the source and drain contacts. A thermodynamics-based approach to the selection of IZO metallization materials is presented along with a study of the microstructural stability of a-IZO metallized with Mo and Ti. In situ transmission electron microscopy (TEM), x-ray diffraction, and atomic force microscopy studies are presented that show that the crystallization temperature of a-IZO metallized with Ti is sharply reduced (to ≅200 °C), while a-IZO metallized with Mo remains amorphous. The effects of the unstable Ti/IZO interface are shown to include: vacancy injection, enhanced amorphous-to-crystal transformation kinetics, interfacial oxide formation, and the lateral growth on adjacent IZO of rutile TiO2 needles.

This is a preview of subscription content, access via your institution.

FIG. 1.
FIG. 2.
FIG. 3.
FIG. 4.
FIG. 5.
FIG. 6.
FIG. 7.
FIG. 8.
TABLE I.

References

  1. 1.

    B. Yaglioglu, H.Y. Yeom, and D.C. Paine: Crystallization of amorphous In2O3-10 wt % ZnO thin films annealed in air. Appl. Phys. Lett. 86, 261908 (2005).

    Article  Google Scholar 

  2. 2.

    H. Hosono: Ionic amorphous oxide semiconductors: Material design, carrier transport, and device application. J. Non-Cryst. Solids 352, 851 (2006).

    CAS  Article  Google Scholar 

  3. 3.

    E. Chong, K.C. Jo, and S.Y. Lee: High stability of amorphous hafnium-indium-zinc-oxide thin film transistor. Appl. Phys. Lett. 96, 152102 (2010).

    Article  Google Scholar 

  4. 4.

    E. Chong, S.H. Kim, and S.Y. Lee: Role of silicon in silicon-indium-zinc-oxide thin-film transistor. Appl. Phys. Lett. 97, 252112 (2010).

    Article  Google Scholar 

  5. 5.

    B. Yaglioglu, H.Y. Yeom, R. Beresford, and D.C. Paine: High-mobility amorphous In2O3-10 wt% ZnO thin film transistors. Appl. Phys. Lett. 89, 062103 (2006).

    Article  Google Scholar 

  6. 6.

    S. Lee, H. Park, and D.C. Paine: The effect of metallization contact resistance on the measurement of the field effect mobility of long-channel unannealed amorphous In–Zn–O thin film transistors. Thin Solid Films 520, 3769 (2012).

    CAS  Article  Google Scholar 

  7. 7.

    J. Nasrullah, G.L. Tyler, and Y. Nishi: An atomic force microscope study of surface roughness of thin silicon films deposited on SiO2. IEEE Trans. Nanotechnol. 4, 303 (2005).

    Article  Google Scholar 

  8. 8.

    K. Nomura, H. Ohta, A. Takagi, T. Kamiya, M. Hirano, and H. Hosono: Room-temperature fabrication of transparent flexible thin-film transistors using amorphous oxide semiconductors. Nature 432, 488 (2004).

    CAS  Article  Google Scholar 

  9. 9.

    A.J. Leenheer, J.D. Perkins, M. van Hest, J.J. Berry, R.P. O’Hayre, and D.S. Ginley: General mobility and carrier concentration relationship in transparent amorphous indium zinc oxide films. Phys. Rev. B 77, 115215 (2008).

    Article  Google Scholar 

  10. 10.

    S. Lee, H. Park, and D.C. Paine: A study of the specific contact resistance and channel resistivity of amorphous IZO thin film transistors with IZO source-drain metallization. J. Appl. Phys. 109, 063702 (2011).

    Article  Google Scholar 

  11. 11.

    B.G. Lewis and D.C. Paine: Applications and processing of transparent conducting oxides. MRS Bull. 25, 22 (2000).

    CAS  Article  Google Scholar 

  12. 12.

    D.C. Paine, T. Whitson, D. Janiac, R. Beresford, C.O. Yang, and B. Lewis: A study of low temperature crystallization of amorphous thin film indium-tin-oxide. J. Appl. Phys. 85, 8445 (1999).

    CAS  Article  Google Scholar 

  13. 13.

    Y.S. Jung, H.Y. Seo, D.W. Lee, and D.Y. Jeon: Influence of DC magnetron sputtering parameters on the properties of amorphous indium zinc oxide thin film. Thin Solid Films 445, 63 (2003).

    CAS  Article  Google Scholar 

  14. 14.

    B. Yaglioglu, Y.J. Huang, H.Y. Yeom, and D.C. Paine: A study of amorphous and crystalline phases in In2O3-10 wt.% ZnO thin films deposited by DC magnetron sputtering. Thin Solid Films 496, 89 (2006).

    CAS  Article  Google Scholar 

  15. 15.

    T. Moriga, D.D. Edwards, T.O. Mason, G.B. Palmer, K.R. Poeppelmeier, J.L. Schindler, C.R. Kannewurf, and I. Nakabayashi: Phase relationships and physical properties of homologous compounds in the zinc oxide-indium oxide system. J. Am. Ceram. Soc. 81, 1310 (1998).

    CAS  Article  Google Scholar 

  16. 16.

    K. Nomura, T. Kamiya, H. Ohta, M. Hirano, and H. Hosono: Defect passivation and homogenization of amorphous oxide thin-film transistor by wet O-2 annealing. Appl. Phys. Lett. 93, 192107 (2008).

    Article  Google Scholar 

  17. 17.

    S. Lee, B. Bierig, and D.C. Paine: Amorphous structure and electrical performance of low-temperature annealed amorphous indium zinc oxide transparent thin film transistors. Thin Solid Films 520, 3764 (2012).

    CAS  Article  Google Scholar 

  18. 18.

    Y. Shimura, K. Nomura, H. Yanagi, T. Kamiya, M. Hirano, and H. Hosono: Specific contact resistances between amorphous oxide semiconductor In-Ga-Zn-O and metallic electrodes. Thin Solid Films 516, 5899 (2008).

    CAS  Article  Google Scholar 

  19. 19.

    P. Barquinha, G. Goncalves, L. Pereira, R. Martins, and E. Fortunato: Effect of annealing temperature on the properties of IZO films and IZO based transparent TFTs. Thin Solid Films 515, 8450 (2007).

    CAS  Article  Google Scholar 

  20. 20.

    J.S. Park, J.K. Jeong, Y.G. Mo, H.D. Kim, and C.J. Kim: Control of threshold voltage in ZnO-based oxide thin film transistors. Appl. Phys. Lett. 93, 033513 (2008).

    Article  Google Scholar 

  21. 21.

    A. Jamshidi-Roudbari, S.A. Khan, and M.K. Hatalis: Integrated full-bit shift register by low-temperature amorphous indium gallium zinc oxide thin-film transistors. Electrochem. Solid-State Lett. 14, J19 (2011).

    CAS  Article  Google Scholar 

  22. 22.

    J.H. Na, M. Kitamura, and Y. Arakawa: High field-effect mobility amorphous InGaZnO transistors with aluminum electrodes. Appl. Phys. Lett. 93, 063501 (2008).

    Article  Google Scholar 

  23. 23.

    J.S. Park, J.K. Jeong, Y.G. Mo, H.D. Kim, and S.I. Kim: Improvements in the device characteristics of amorphous indium gallium zinc oxide thin-film transistors by Ar plasma treatment. Appl. Phys. Lett. 90, 262106 (2007).

    Article  Google Scholar 

  24. 24.

    W.S. Kim, Y.K. Moon, K.T. Kim, J.H. Lee, B.D. Ahn, and J.W. Park: An investigation of contact resistance between metal electrodes and amorphous gallium-indium-zinc oxide (a-GIZO) thin-film transistors. Thin Solid Films 518, 6357 (2010).

    CAS  Article  Google Scholar 

  25. 25.

    A. Sato, K. Abe, R. Hayashi, H. Kumomi, K. Nomura, T. Kamiya, M. Hirano, and H. Hosono: Amorphous In-Ga-Zn-O coplanar homojunction thin-film transistor. Appl. Phys. Lett. 94, 133502 (2009).

    Article  Google Scholar 

  26. 26.

    W.T. Lim, D.P. Norton, J.H. Jang, V. Craciun, S.J. Pearton, and F. Ren: Carrier concentration dependence of Ti/Au specific contact resistance on n-type amorphous indium zinc oxide thin films. Appl. Phys. Lett. 92, 122102 (2008).

    Article  Google Scholar 

  27. 27.

    S. Lee and D.C. Paine: On the effect of Ti on the stability of amorphous indium zinc oxide used in thin film transistor applications. Appl. Phys. Lett. 98, 262108 (2011).

    Article  Google Scholar 

  28. 28.

    D.R. Lide: Standard thermodynamic properties of chemical substances, in CRC Handbook of Chemistry and Physics (CRC Press, 80th edition, New York, NY, 1999).

    Google Scholar 

  29. 29.

    R. Beyers: Thermodynamic considerations in refractory metal-silicon-oxygen systems. J. Appl. Phys. 56, 147 (1984).

    CAS  Article  Google Scholar 

  30. 30.

    J.C. Riviere: In Solid State Surface Science, M. Green, ed. (Marcel Dekker, Vol. 1, New York, 1969) p. 179.

    CAS  Google Scholar 

  31. 31.

    J. Hölzl and F.K. Schulte: Solid Surface Physics, in Springer Tracts of Modern Physics, G. Höhler, ed. (Springer, Vol. 85, Berlin, Germany, 1979).

Download references

Acknowledgment

The authors gratefully acknowledge the financial support of the National Science Foundation (NSF) Award No. DMR-0804915.

Author information

Affiliations

Authors

Corresponding author

Correspondence to David C. Paine.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Lee, S., Park, K. & Paine, D.C. Metallization strategies for In2O3-based amorphous oxide semiconductor materials. Journal of Materials Research 27, 2299–2308 (2012). https://doi.org/10.1557/jmr.2012.141

Download citation