In-Situ Real-Time Ellipsometry Study of Dynamic Processes of YBa2Cu3O7−x Thin Films

1999 ◽  
Vol 569 ◽  
Author(s):  
Y. Gao ◽  
A.H. Mueller ◽  
E.A. Irene ◽  
O. Auciello ◽  
A.R. Krauss ◽  
...  

ABSTRACTThe optical absorption peak at 4. leV associated with oxygen deficiency in YBa2Cu3O7−x thin films was monitored by spectroscopic ellipsometry (SE) in real time during the growth process. Two regimes dominated by oxygen out- and in-diffusion have been observed during deposition by ion beam sputtering at 700°C.The effect of oxygen partial pressure during the post-deposition cooling process on the oxidation of deposited films has also been investigated. The thermodynamic stability of the grown films was examined by real time SE during post annealing process. In-situ SE measurements have been performed to obtain the dielectric function of oxygen deficient YBa2Cu3O6 films in the temperature range from 27°C to 700°C. It has been demonstrated that real time SE is a sensitive and useful technique for in-situ diagnostics of the dynamics of YBa2Cu3O7−x thin film processes.

1991 ◽  
Vol 27 (2) ◽  
pp. 2522-2524 ◽  
Author(s):  
S. Barbanera ◽  
F. Murtas ◽  
L. Scopa ◽  
V. Boffa ◽  
G. Paterno ◽  
...  

2018 ◽  
Vol 482 ◽  
pp. 203-207 ◽  
Author(s):  
Lishuan Wang ◽  
Yugang Jiang ◽  
Chenghui Jiang ◽  
Huasong Liu ◽  
Yiqin Ji ◽  
...  

1992 ◽  
Vol 7 (8) ◽  
pp. 2003-2016 ◽  
Author(s):  
J.A. Kittl ◽  
W.L. Johnson ◽  
C.W. Nieh

We investigated the in situ growth of YBa2Cu3O7−δ superconducting thin films by a sequential ion beam sputtering technique, studying the relations among deposition parameters, structural and superconducting properties. The films were deposited following the stacking sequence of YBa2Cu3O7−δ, with individual layer thicknesses nominally equal to one monolayer. O2 was supplied during deposition. Predominantly c-axis oriented films were grown on (100) SrTiO3, (100) MgO, and oxidized Si (SiO2/Si) substrates. The microstructure and film-substrate orientation relations were studied by transmission electron microscopy. X-ray studies showed the presence of homogeneous and inhomogeneous strains along the c-direction that persisted after low temperature oxygen anneals. Resistivity measurements showed correlations between the superconducting transition characteristics and the lattice distortions along the c-direction. The effect of deposition parameters on the lattice distortions was investigated, finding that the c-axis lattice parameter was larger in films grown at lower temperatures. This was interpreted in terms of the thermally activated dissociation of O2 at the film surface during growth. We assumed that the c-axis lattice expansion was due to kinetic limitations to the incorporation of oxygen into the film during growth. This led to a consistent description of the results obtained in this work and the O2 pressure dependence of the c-axis lattice expansion reported for other in situ techniques. Studies were performed on films grown by this technique as well as on films grown in situ by magnetron sputtering in an attempt to elucidate the nature of the defect structure causing the c-axis lattice distortions.


1995 ◽  
Vol 10 (2) ◽  
pp. 274-279 ◽  
Author(s):  
Hae Seok Cho ◽  
Sang Ki Ha ◽  
Min Hong Kim ◽  
Hyeong Joon Kim

We deposited (Mn,Zn,Fe)1−xO thin films of a wüstite structure on SiO2/Si(100) by ion beam sputtering using a single-crystal Mn-Zn ferrite target. The wüstite structure of the as-deposited film, confirmed by XRD, TEM, and XPS analysis, appeared to originate from an oxygen-deficit ambient and also from the preferential resputtering of the oxygen ions in films during deposition. The as-deposited films showed ferrimagnetic characteristics having quite a large Ms in spite of their crystallographic structure, wüstite. Such an unusual phenomenon is presumably due to the different magnetic moments of the constituent cations with disordered distribution. This wüstite phase could be transformed into the spinel ferrite phase with the same preferred orientation during postannealing under an appropriate oxygen partial pressure. The interplanar distance of the as-deposited films decreased with increasing Ts due to a release of compressive stress. The Ms of the film had a maximum value at about 275 °C, while the resistivity, mainly governed by the grain boundaries, was almost the same irrespective of Ts.


1993 ◽  
Vol 21 (1) ◽  
pp. 5-9 ◽  
Author(s):  
A.V. Bagulya ◽  
I.P. Kazakov ◽  
M.A. Negodaev ◽  
V.I. Tsekhosh ◽  
V.V. Voronov

1990 ◽  
Vol 9 (9) ◽  
pp. 336-338 ◽  
Author(s):  
J.A. Kittl ◽  
C.W. Nieh ◽  
D.S. Lee ◽  
W.L. Johnson

1993 ◽  
Vol 8 (12) ◽  
pp. 3032-3042 ◽  
Author(s):  
B.J. Kellett ◽  
J.H. James

This article addresses issues associated with in situ growth of superconducting YBa2Cu3O7−δ thin films by ion beam sputtering. High oxygen partial pressure during ion beam deposition can cause significant beam broadening and oxidation of filaments and grids. Also, many of the targets used for processing YBCO are unstable when sputtered in a high oxygen partial pressure. It is shown that ion beam sputtering can produce YBCO films of comparable quality to those produced by laser ablation or dc magnetron sputtering. Typical film properties are Tco = 91 K and Jc (77 K) = 106 A cm−2. It appears that the oxygen gas pressure during the postdeposition cooldown has a more important influence on film properties than the oxygen partial pressure during deposition.


1993 ◽  
Vol 317 ◽  
Author(s):  
Hae Seok Cho ◽  
Sang Ki Ha ◽  
Min Hong Kim ◽  
Hyeong Joon Kim

ABSTRACTWe investigated the effects of the substrate temperature (Ts) on the crystallization and the development of texture of Mn-Zn ferrite thin films on SiO2/Si (100) under ion bombardment during ion beam sputtering. As-deposited films showed ferrimagnetic properties in spite of their crystallographic structure of wustite. The crystallographic structure of as-deposited films changed from (111) wustite structure to (222) spinel structure as oxygen partial pressure increased. The (222) preferred orientation seems to originate from oxygen-deficit ambient and preferential resputtering of oxygen ions in films during sputtering. The interplanar distance of the films deposited without oxygen flow decreased with increasing Ts due to release of compressive stress. The saturation Magnetization (Ms) of the film had maximum value at about 275°C, while the resistivity was almost of the same value irrespective of Ts. The unusual fact that crystallization and preferred orientation were less progressed at higher Ts was discussed.


1989 ◽  
Vol 169 ◽  
Author(s):  
B.J. Kellett ◽  
J.H. James ◽  
A. Gauzzi ◽  
M. Affronte ◽  
D. Pavuna

AbstractSuperconducting YBa2Cu3O7‐δ (YBCO) films 100‐300nm thick have been grown in‐situ on (100) SrTiO3 at 650°C by ion beam sputtering. Targets of Cu, CuO, Y, Y2O3, BaF2, BaCO3 and YBa2Cu3O7‐δ have been studied. Uniform composition throughout the film thickness has been achieved by co‐sputtering. Films are metallic (p300=300μΩcm) and textured, with Tc onsets at 92K and Tco=82K. Jc(77K) exceeds 105 Acm‐2. Films grown in‐situ on Si with ZrOx/Y2O3 and In2O3(10 at.%SnO2) buffer layers show Tc onsets at about 90K and Tco at about 50K, annealing improves Tco to 60K with resistivities p30o=2000μΩcm and 4000μΩcm respectively.


Author(s):  
J. S. Maa ◽  
Thos. E. Hutchinson

The growth of Ag films deposited on various substrate materials such as MoS2, mica, graphite, and MgO has been investigated extensively using the in situ electron microscopy technique. The three stages of film growth, namely, the nucleation, growth of islands followed by liquid-like coalescence have been observed in both the vacuum vapor deposited and ion beam sputtered thin films. The mechanisms of nucleation and growth of silver films formed by ion beam sputtering on the (111) plane of silicon comprise the subject of this paper. A novel mode of epitaxial growth is observed to that seen previously.The experimental arrangement for the present study is the same as previous experiments, and the preparation procedure for obtaining thin silicon substrate is presented in a separate paper.


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