Search / Korean Journal of Chemical Engineering
HWAHAK KONGHAK,
Vol.31, No.2, 131-136, 1993
화학증착법에 의한 Y-Ba-Cu-O계 고온 초전도 박막 제조에 있어서 기판의 표면상태에 따른 박막의 특성변화 연구
A Study on the Property changes According to Surface States of Substrate in the Preparation of Y-Ba-Cu-O High-TC Superconducting Thin Films by Chemical Vapor Deposition
고온 초전도 박막을 전자장치에 이용할 반도체 소자로서 사용하기 위해서는 가능한한 낮은 온도에서 제조되어야 하며, 매끄러운 표면과 균일한 미세구조를 갖고 있어야 한다. 기판의 표면상태에 따른 초전도 박막의 특성 변화를 살펴보기 위하여 as-prepared 상태의 MgO(100) 기판과 15N HNO3용액에 1시간 동안 식각한 MgO(100)기판을 사용하였다. 본 연구에서 화학증착법으로 Y계 고온 초전도 박막을 후열처리 없이 제조하였으며, 원료물질과 반응가스는 각각 β-diketone 킬레이트 화합물과 O2를 사용하였다. 650℃의 증착온도와 0.0126torr의 산소 분압하에서, 식각되지 않은 기판에 증착한 박막이 식각된 기판에 증착한 박막보다 초전도 특성이 우수한 것으로 확인되었다.
Since the discovery of superconducting oxides, enormous amount of research has been conducted on the preparation of high-TC superconducting films. It is obvious that future microelectronic devices will require well-crystallized films of smooth surface and uniform structure prepared at substrate temperatures as low as possible. The high-TC superconducting Y-Ba-Cu-O thin films in this work were prepared by thermal chemical vapor deposition method on MgO(100) substrate without postannealing using β-diketone metal chelates of Y(thd)3, Ba(thd)2, and Cu(thd)2 as source materials and O2 as a reactant gas. Superconductivity above liquid nitrogen temperature(TC,onset=90.1K and TC,O=87.3K) was obtained for the film prepared at 650℃ and 0.0126torr. The thin films consisted of Y-Ba-Cu-O with mostly c-axis perpendicular to the substrate plane and with small amounts of a-axis normal to film surface.
[References]
  1. Berry AD, Gaskill DK, Holm RT, Cukauskas EJ, Kaplan R, Henry RL, Appl. Phys. Lett., 52(20), 1743, 1988
  2. Yamane H, Masumoto H, Hirai T, Iwasaki H, Watanabe K, Kobayashi N, Muto Y, Appl. Phys. Lett., 53(16), 1548, 1988
  3. Yamane H, Kurosawa H, Hirai T, Watanabe K, Iwasaki H, Kobayashi N, Muto Y, J. Cryst. Growth, 98, 860, 1989
  4. Yamane H, Kurosawa H, Suhara A, Hirai T, Watanabe K, Iwasaki H, Kobayashi N, Muto Y, Mol. Cryst. Liq. Cryst., 184, 343, 1990
  5. Tsuruoka T, Kawasaki R, Abe H, Jpn. J. Appl. Phys., 28(10), L1800, 1989
  6. Ohnishi H, Harima H, Kusakabe Y, Kobayashi M, Hoshinouchi S, Tachibana K, Jpn. J. Appl. Phys., 29(11), L2041, 1991
  7. Li YQ, Zhao J, Chern CS, Lemoine EE, Gallios B, Norris P, Kear B, Appl. Phys. Lett., 58(20), 2300, 1991
  8. Kanehori K, Sughii N, Fukazawa T, Miyauchi K, Thin Solid Films, 182, 265, 1989
  9. Yamane H, Hasei M, Kurosawa H, Hirai T, Jpn. J. Appl. Phys., 30(6A), L1003, 1991
  10. Lee HG, Park SD, Yang SW, Shin HS, Won DY, Jpn. J. Appl. Phys., 31(2), 1992
  11. Lee HG, Park SD, Yang SW, Shin HS, Won DY, Physica C, in press
  12. Hammond RH, Bormann R, Physica C, 162-164, 703, 1989
  13. Eisentraut KJ, Sievers RE, J. Inorg. Nucl. Chem., 29, 1931, 1967
  14. Moeckly BH, Russek SE, Lathrop DK, Buhrman RA, Li J, Mayer JW, Appl. Phys. Lett., 57(16), 1687, 1990
  15. Zhao J, Li YQ, Chern CS, Norris P, Gallois B, Kear B, Wessels BW, Appl. Phys. Lett., 58(1), 89, 1991
  16. Dwir B, Affronte M, Pavuna D, Appl. Phys. Lett., 55(4), 399, 1989
  17. Miller JH, Holder SL, Hunn JD, Appl. Phys. Lett., 54(22), 2256, 1989