Grain morphology and cation composition heterogeneity of Pb(ZrxTi1–x)O3 thin films deposited by metal-organic chemical vapor deposition

1998 ◽  
Vol 13 (6) ◽  
pp. 1614-1625 ◽  
Author(s):  
I-Fei Tsu ◽  
G-R. Bai ◽  
C. M. Foster ◽  
K. L. Merkle ◽  
K. C. Liu

The preferred orientation, grain morphology, and composition heterogeneity of the polycrystalline Pb(ZrxTi1–x)O3 (PZT) thin films were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), and x-ray energy dispersive spectroscopy (EDS). PZT thin films with nominal x = 0.5 were grown by metal-organic chemical vapor deposition (MOCVD) on (110)- and (101)-textured RuO2 bottom electrodes at temperatures ≤525 °C. Columnar grain microstructure with strongly faceted surface morphology was observed in both films. The grain morphology and surface roughness of the PZT films were observed to depend on those of the underlying RuO2 layers. TEM-EDS analysis shows notable cation composition heterogeneity in length scales of 0.2–2 μm. Pronounced Pb composition deficiency and heterogeneity were also observed in PZT/(110)RuO2 in length scales above 40 μm. The grain morphology and cation heterogeneity of the PZT films are discussed on the basis of diffusion-limited columnar growth mechanism.

1993 ◽  
Vol 335 ◽  
Author(s):  
Bruce J. Hinds ◽  
Jon L. Schindler ◽  
Bin Han ◽  
Deborah A. Neumayer ◽  
Donald C. Degroot ◽  
...  

AbstractSuperconducting thin films of Tl2Ba2Ca2Cu3O10−x (TL-2223) have been grown on single crystal (110) LaAlO3 using a two-step process. Ba2Ca2Cu3Ox precursor films are deposited via metal-organic chemical vapor deposition (MOCVD) in a horizontal hot walled reactor. The second generation precursors Ba(hfa)2•tet, Ca(hfa)2•tet, and Cu(hfa)2 (hfa = hexafluoroacetylacetonate, tet = tetraglyme) were used as volatile metal sources due to their superior volatility and stability. Tl was introduced into the film via a high temperature post anneal in the presence of a Tl2O3:BaO:CaO:CuO pellet (1:2:2:3 ratio). Low O2 partial pressures were used to reduce the temperature in which the TI-2223 phase forms and to improve the surface morphology associated with a liquid phase intermediate. Films are highly oriented with the c-axis perpendicular to the substrate and a-b axis epitaxy is seen from x-ray φ- scans. The best films have a resistively measured Tc of 115K and a magnetically derived Jc of 6×105 A/cm2 (77K, 0 T). Preliminary surface resistance measurements, using parallel plate techniques, give Rs = 0.35 mΩ at 5K (ω = 10 GHz).


1992 ◽  
Vol 275 ◽  
Author(s):  
D. L. Schulzi ◽  
B. Hano ◽  
D. Neumayer ◽  
B. J. Hinds ◽  
T. J. Markst ◽  
...  

ABSTRACTThe synthesis of superconducting Tl-Ba-Ca-Cu-O thin films on metal foils (Au and Ag) by metal-organic chemical vapor deposition (MOCVD) has been investigated. Ba-Ca-Cu-O-(F) films are first prepared via MOCVD using fluorinated “second generation” metal-organic precursors. After an intermediate anneal with water vapor-saturated oxygen to promote removal of F, Tl is introduced by annealing in the presence of a mixture of oxides (Tl2O3, BaO, CaO, CuO) of a specific composition. Characterization of the thin films by scanning electron microscopy, EDX, x-ray diffraction, and variable temperature magnetization measurements has been carried out. High temperature superconductor (HTS) films of Tl2Ba2Ca1Cu2O8−x on Au foil exhibit a magnetically derived Tc = 80K and a high degree of texturing with the crystallite c-axes oriented perpendicular to the substrate surface as evidenced by enhanced (000 x-ray diffraction reflections. Thin film coverage on Ag foil becomes non-contiguous during the (Tl2O3, BaO, CaO, CuO) mixture anneal.


2004 ◽  
Vol 449-452 ◽  
pp. 997-1000 ◽  
Author(s):  
Gwang Pyo Choi ◽  
Yong Joo Park ◽  
Whyo Sup Noh ◽  
Jin Seong Park

Tin oxide thin films were deposited at 375 °C on α-alumina substrate by metal-organic chemical vapor deposition (MOCVD) process. A number of hillocks on the film were formed after air annealing at 500 °C for 30 min and few things in N2 annealing. The oxygen content and the binding energy after air annealing came to close the stoichiometric SnO2. The cauliflower hillocks of the film seem to be formed by the continuous migration of crystallites from a cauliflower grain on the substrate to release the stress due to the increase of oxygen content and volume.


2007 ◽  
Vol 515 (5) ◽  
pp. 2921-2925 ◽  
Author(s):  
Chunyu Wang ◽  
Volker Cimalla ◽  
Genady Cherkashinin ◽  
Henry Romanus ◽  
Majdeddin Ali ◽  
...  

2003 ◽  
Vol 42 (Part 1, No. 5A) ◽  
pp. 2839-2842 ◽  
Author(s):  
Jeong Hoon Park ◽  
Kug Sun Hong ◽  
Woon Jo Cho ◽  
Jang-Hoon Chung

1994 ◽  
Vol 9 (7) ◽  
pp. 1721-1727 ◽  
Author(s):  
Jie Si ◽  
Seshu B. Desu ◽  
Ching-Yi Tsai

Synthesis of zirconium tetramethylheptanedione [Zr(thd)4] was optimized. Purity of Zr(thd)4 was confirmed by melting point determination, carbon, and hydrogen elemental analysis and proton nuclear magnetic resonance spectrometer (NMR). By using Zr(thd)4, excellent quality ZrO2 thin films were successfully deposited on single-crystal silicon wafers by metal-organic chemical vapor deposition (MOCVD) at reduced pressures. For substrate temperatures below 530 °C, the film deposition rates were very small (⋚1 nm/min). The film deposition rates were significantly affected by (i) source temperature, (ii) substrate temperature, and (iii) total pressure. As-deposited films are carbon free. Furthermore, only the tetragonal ZrO2 phase was identified in as-deposited films. The tetragonal phase transformed progressively into the monoclinic phase as the films were subjected to a high-temperature post-deposition annealing. The optical properties of the ZrO2 thin films as a function of wavelength, in the range of 200 nm to 2000 nm, were also reported. In addition, a simplified theoretical model which considers only a surface reaction was used to analyze the deposition of ZrO2 films. The model predicated the deposition rates well for various conditions in the hot wall reactor.


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