TY - JOUR
T1 - Atomic layer-by-layer epitaxy of oxide superconductors by MOCVD
AU - Yamamoto, Shuu'ichirou
AU - Kawaguchi, Atsushi
AU - Nagata, Kouji
AU - Hattori, Takeo
AU - Oda, Shunri
N1 - Funding Information:
This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture, by NEDO under the management of FED, and by the Yazaki Memorial Foundation.
PY - 1997/3
Y1 - 1997/3
N2 - We have prepared thin films of c-axis oriented YBa 2 Cu 3 O x (YBCO) with a very smooth surface and roughness of less than a monomolecular layer of YBCO by atomic layer-by-layer metalorganic chemical vapor deposition on SrTiO 3 (100) and NdGaO 3 (110) substrates. A YBCO film with a large terrace width of 660 nm has been obtained on a NdGaO 3 (110) substrate. We have clarified the correlation between boulder formation and dislocations in the substrates by atomic force microscope observation. We have attempted to avoid producing boulder nuclei on dislocations exposed on the substrate surface by changing the usual sequence of source supply, Ba/Cu/Ba/Cu/Y/Cu, for 1 cycle into a new sequence, Ba/Ba/Y/Cu/Cu/Cu, and have successfully prevented the boulders. We also discuss issues of third generation precursors which are used in the liquid phase. We have also investigated hetero epitaxy of Sm 2 O 3 ultrathin insulating films on YBCO thin films.
AB - We have prepared thin films of c-axis oriented YBa 2 Cu 3 O x (YBCO) with a very smooth surface and roughness of less than a monomolecular layer of YBCO by atomic layer-by-layer metalorganic chemical vapor deposition on SrTiO 3 (100) and NdGaO 3 (110) substrates. A YBCO film with a large terrace width of 660 nm has been obtained on a NdGaO 3 (110) substrate. We have clarified the correlation between boulder formation and dislocations in the substrates by atomic force microscope observation. We have attempted to avoid producing boulder nuclei on dislocations exposed on the substrate surface by changing the usual sequence of source supply, Ba/Cu/Ba/Cu/Y/Cu, for 1 cycle into a new sequence, Ba/Ba/Y/Cu/Cu/Cu, and have successfully prevented the boulders. We also discuss issues of third generation precursors which are used in the liquid phase. We have also investigated hetero epitaxy of Sm 2 O 3 ultrathin insulating films on YBCO thin films.
KW - Atomic force microscope (AFM)
KW - Liquid precursor
KW - Metalorganic chemical vapor deposition (MOCVD)
KW - Preferential growth
KW - Surface migration
KW - YBa Cu O
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U2 - 10.1016/S0169-4332(96)01005-7
DO - 10.1016/S0169-4332(96)01005-7
M3 - Article
AN - SCOPUS:0031546912
VL - 112
SP - 30
EP - 37
JO - Applied Surface Science
JF - Applied Surface Science
SN - 0169-4332
ER -