Ultra-Smooth ZnO Buffer Layers on (001) Sapphire


Using off-axis reactive rf sputtering, we have grown extremely smooth, nearly epitaxial, (001) oriented ZnO films on c-axis sapphire substrates. Atomic Force Microscopy was used to determine that these films are extremely smooth, having an rms roughness of only a few tenths of a nanometer. Based on high resolution x-ray diffraction (HXRD), the ZnO is highly oriented, with a rocking curve width of less than 400 arc seconds for the (006) diffraction peak, and only somewhat larger for the (112) reflection. HXRD Phi scans show that the ZnO (112) reflection is rotated in the a-b plane by 30 degrees from the sapphire (113) direction. These two measurements indicate excellent in-plane orientation. We are investigating the use of these buffer layers for subsequent GaN growth. Electrical resistivities of the films exceeded 100 kΩ-cm making ZnO a potential candidate as an insulating buffer layer.

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  1. 1.

    T. Peng, J. Pipek, G. Qiu, J.O. Olowolafe, K.M. Unruh, C.P. Swann, and E.F. Schubert, Appl. Phys. Lett., 71, 2439 (1997).

    CAS  Article  Google Scholar 

  2. 2.

    T. Matsuoka, N. Yoshimoto, T. Sasaki, A. Katsui, J. Electron. Mater. 21, 157 (1992).

    CAS  Article  Google Scholar 

  3. 3.

    E.S. Hellman, D. N. E. Buchanan, D. Wiesmann, I. Brener, MRS Internet Journal, Vol.1, Article 16 (1996), http://nsr.mij.mrs.org/l/16/complete.html

  4. 4.

    S. Strite and H. Morkoc, J. Vac. Sci. Technol. B. 10, 1237 (1992).

    CAS  Article  Google Scholar 

  5. 5.

    T. Detchprohm, K. Hiramatsu, H. Amano, and I. Akasaki, Appl. Phys. Lett., 61, 2688 (1992).

    CAS  Article  Google Scholar 

  6. 6.

    Syuichi Takada, J. Appl. Phys., 73, 4739 (1993).

    CAS  Article  Google Scholar 

  7. 7.

    Jwo-Huei Jou, Min-Yung Han, and Duen-Jen Cheng, J. Appl. Phys., 71, 4333 (1992).

    CAS  Article  Google Scholar 

  8. 8.

    Yasuhiro Igasaka and Hiromi Saito, J. Appl. Phys., 70, 3613 (1991).

    Article  Google Scholar 

  9. 9.

    H. Czternastek, A. Brudnik, M. Jachimowski and E. Kolawa, J. Phys. D: Appl. Phys. 25, 865 (1992).

    CAS  Article  Google Scholar 

  10. 10.

    A.J. Drehman, P.W. Yip, Proc. MRS, III-V Nitrides, 449, 337 (1997).

    CAS  Article  Google Scholar 

  11. 11.

    H. Nanto, T. Minami, S. Shooji, and S. Takata, J. Appl. Phys., 55, 1029 (1984).

    CAS  Article  Google Scholar 

  12. 12.

    R.D. Vispute, V. Talyansky, Z. Trajanovic, S. Choopun, M. Downes, R.P. Sharma, T. Venkatesan, M.C. Wood, R.T. Lareau, K.A. Jones and A.A. Iliadis, Appl. Phys. Lett., 70, 2735 (1997).

    CAS  Article  Google Scholar 

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Drehman, A.J., Wang, SQ. & Yip, P.W. Ultra-Smooth ZnO Buffer Layers on (001) Sapphire. MRS Online Proceedings Library 482, 358–363 (1997). https://doi.org/10.1557/PROC-482-289

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