Growth and Properties of Epitaxial YBa2Cu3O7 thin Films on{1102}Al2O3

1989 ◽  
Vol 169 ◽  
Author(s):  
D. K. Fork ◽  
T. H. Geballe ◽  
K. Char ◽  
S. S. Laderman ◽  
R. Taber ◽  
...  

AbstractEpitaxial YBa2Cu3O7 (YBCO) films were grown on r‐plane A12O3 {1102} by laser ablation. X‐ray diffraction shows that films are epitaxial with the c‐axis perpendicular to the substrate and the a or b axes parallel to (2201), although the full width at half maximum of the rocking curve is larger compared to those of epitaxial films on SrTiO3. The critical temperatures (zero resistance) are between 85 K and 88 K with transition widths between 0.5 K and 3 K. The 300 K resistivity of 250 μΩextrapolates to zero at zero temperature and the critical current is as high as 5 x 106 A/cm2 at 4.2 K according to magnetization hysteresis measurements. Surface resistance data shows that 2000 Å thick epitaxial films on {1102} have about 1 mΩ at 13 GHz at 4.2 K.

1999 ◽  
Vol 595 ◽  
Author(s):  
W.L. Sarney ◽  
L. Salamanca-Riba ◽  
V. Ramachandran ◽  
R.M Feenstra ◽  
D.W. Greve

AbstractGaN films grown on SiC (0001) by MBE at various substrate temperatures (600° - 750° C) were characterized by RHEED, STM, x-ray diffraction, AFM and TEM. This work focuses on the TEM analysis of the films' features, such as stacking faults and dislocations, which are related to the substrate temperature. There are several basal plane stacking faults in the form of cubic inclusions for samples grown at low temperatures compared to those grown at high temperatures. The dislocation density is greatest for the film grown at 600°C, and it steadily decreases with increasing growth temperatures. Despite the presence of various defects, x-ray analysis shows that the GaN films are of high quality. The double crystal rocking curve full width at half maximum (FWHM) for the GaN (0002) peak is less than 2 arc-minutes for all of the films we measured and it decreases with increasing growth temperature.


1997 ◽  
Vol 12 (4) ◽  
pp. 1017-1021 ◽  
Author(s):  
Shara S. Shoup ◽  
Mariappan Paranthaman ◽  
David B. Beach ◽  
E. D. Specht ◽  
Robert K. Williams

A LaAlO3 precursor solution was prepared via an all alkoxide sol-gel route. The solution of lanthanum methoxyethoxide and aluminum methoxyethoxide in 2-methoxyethanol was prepared via ligand exchange starting from lanthanum isopropoxide and aluminum sec-butoxide and was used to make both LaAlO3 powders and films. Complete hydrolysis of the solution formed a gel that yielded well-crystallized LaAlO3 powders when fired in air at 800 °C. A partially hydrolyzed solution was spun-cast on SrTiO3 (100) single crystal substrates. Epitaxial films of LaAlO3 were subsequently formed during pyrolysis in O2 at 800 °C in a rapid thermal annealing furnace for a total of 8 min. The films were strongly c-axis oriented, verified by x-ray rocking curve results from the (003) plane with full-width at half-maximum (FWHM) = 0.87°, and had good in-plane texture shown by a φ scan of the (202) plane with FWHM = 1.07°.


1997 ◽  
Vol 12 (5) ◽  
pp. 1297-1305 ◽  
Author(s):  
C. D. Theis ◽  
D. G. Schlom

Epitaxial PbTiO3 films have been grown on vicinal (001) SrTiO3 substrates by pulsed laser deposition. Vicinal SrTiO3 substrates with misorientations up to 9° from (001) were used, and the influence of the direction of misorientation on the resulting domain structure was studied. 4-circle x-ray diffraction analysis indicates that thin (40 nm) PbTiO3 films are completely c-axis oriented [rocking curve full-width-at-half-maximum (FWHM) of 0.25° for the 002 reflection] and that thicker films (∼ 200 nm) contain mixed a-axis and c-axis PbTiO3 domains due to twinning along {011} planes. The [100] axis of the a-axis domains is misoriented by 2.1° to 3.3° toward 〈100〉 substrate directions with respect to the substrate normal. In contrast to growth on well-oriented (001) SrTiO3 surfaces where the four equivalent tilts of the [100] axis of the a-axis domains are equally likely, on vicinal SrTiO3 the a-axis domains are preferentially oriented in an uphill direction with respect to the crystallographic miscut.


1992 ◽  
Vol 275 ◽  
Author(s):  
Koichi Mizuno ◽  
Yo Ichikawa ◽  
Kentaro Setsune

ABSTRACTCrystalline quality of Bi-based oxide films has been evaluated by means of X-ray diffraction (XRD) and ion-channeling on the Rutherford backscattering (RBS). The films were sputter deposited 2201-phase Bi2Sr2Cu1O8-δ (BSCO) and 2212-phase Bi2Sr2Ca1Cu2O8-δ (BSCCO). They were prepared on MgO(100) and SrTiO3(100) substrates at the low temperature of 650°C during the deposition. The best quality, however thin films had poor crystallinity compared to single crystals, was obtained with the 2201-phase BSCO film that was deposited on a SrTiO3(100) substrate. The full width at half maximum (FWHM) value of the rocking curve on XRD for the film was estimated as 1560 (arc sec).


2002 ◽  
Vol 721 ◽  
Author(s):  
P. Kuppusami ◽  
S. Fiechter ◽  
K. Ellmer

AbstractAluminium-doped zinc oxide (ZnO:Al) films have been grown on c-plane (001) and a-plane (110) sapphire by RF magnetron sputtering from a ceramic target. The films grew epitaxially, even at room temperature. However, the crystalline quality depends both on the substrate temperature as well as on the sapphire orientation. The best films, proved by X-ray diffraction (rocking curves and pole figure measurements) were grown on (110)-oriented sapphire in the temperature range 473 to 773 K. The minimum rocking curve half width was about 0.75 °. By Rutherford backscattering analysis it could be shown, that the films exhibit a significant variation of the defect density over the film thickness. The highest density, as expected, is observed at the interface sapphire/ZnO:Al. Films grown on (001)-oriented sapphire have higher rocking curve half widths (about 1.3 °) and exhibit sometimes two types of domains in the same film twisted by 30 °.


Author(s):  
В.Н. Бессолов ◽  
М.Е. Компан ◽  
Е.В. Коненкова ◽  
В.Н. Пантелеев

A new approach is proposed to the synthesis of a semipolar AlN on a Si(100) substrate at the surface for which the angle between the inclined plane of the nanogrooves and Si(100) is 47°. It is shown that the hydride vapor-phase epitaxy on a such nano-patterned substrate enables formation of a semipolar layer AlN (1012) characterized by the full width at half maximum value as low as ωθ ~60 arcmin for the x-ray diffraction rocking curve. It is found that the Raman spectra of the semipolar AlN(10-12) layer contain additional peaks on the Raman curves associated with phonons A1(TO) and E1(TO), in contrast to the polar AlN(0001) layer, where the peak A1(LO) is additionally manifested.


1992 ◽  
Vol 280 ◽  
Author(s):  
B K Tanner ◽  
T D Hallam ◽  
M Funaki ◽  
A W Brinkman

ABSTRACTEpitaxial films of Hg1-xMnxTe (MMT) have been grown by direct alloy growth MOVPE. Perfection of layers grown on CdTe buffered GaAs, and unbuffered CdZnTe substrates has been assessed by double axis X-ray diffraction. No significant difference was observed in the rocking curve full width at half maximum (FWHM) between layers grown on the two types of substrate. Rocking curves taken as a function of position across the layer showed substantial variation, there being a very good correlation between layer thickness determined from the intensity of the substrate peak, layer rocking curve FWHM and Mn composition determined from the substrate and layer peak splitting. The contour maps of these parameters are discussed in terms of depletion of the DIPTe precursor.


2000 ◽  
Vol 5 (S1) ◽  
pp. 238-244
Author(s):  
W.L. Sarney ◽  
L. Salamanca-Riba ◽  
V. Ramachandran ◽  
R.M Feenstra ◽  
D.W. Greve

GaN films grown on SiC (0001) by MBE at various substrate temperatures (600° - 750° C) were characterized by RHEED, STM, x-ray diffraction, AFM and TEM. This work focuses on the TEM analysis of the films’ features, such as stacking faults and dislocations, which are related to the substrate temperature. There are several basal plane stacking faults in the form of cubic inclusions for samples grown at low temperatures compared to those grown at high temperatures. The dislocation density is greatest for the film grown at 600°C, and it steadily decreases with increasing growth temperatures. Despite the presence of various defects, x-ray analysis shows that the GaN films are of high quality. The double crystal rocking curve full width at half maximum (FWHM) for the GaN (0002) peak is less than 2 arc-minutes for all of the films we measured and it decreases with increasing growth temperature.


1985 ◽  
Vol 54 ◽  
Author(s):  
Jharna Chaudhuri ◽  
William E. Mayo ◽  
Sigmund Weissmann

ABSTRACTA new x-ray diffraction method is developed to determine the full elastic strain tensor and its distribution about a strain center in single crystal materials. It is based on the recently developed Computer Aided Rocking Curve Analyzer and is particularly well suited for analysis of thin film structures common to electronic materials. This technique will be described in detail, and its application in measuring the non-uniform strains in InGaAsP epitaxial film on InP substrate will be presented. Also, possibility of using this method to measure the uniformity of film thickness will be discussed.


1998 ◽  
Vol 541 ◽  
Author(s):  
E Tokumitsu ◽  
Y. Takahashi ◽  
H. Ishiwara

AbstractWe report the preparation and characterization of Bi2VO5.5(BVO) films grown on SrTiO3, Pt/SiO2/Si, and n-Si(100) substrates by the MOD technique. Since a dielectric constant of BVO is much lower than that of PZT or SBT, BVO is one of the promising candidates for metal-ferroelectric-semiconductor field-effect transistors (MFSFETs). It is found by X-ray diffraction (XRD) measurements that highly (001)-oriented BVO films were obtained and that the crystalline quality was improved with increasing the annealing temperature. The full width at half maximum (FWHM) in the X-ray rocking curve measurements for BVO films on SrTiO3, Pt/SiO2/Si, and n-Si(100) substrates are 0.60, 1.00, and 5.10, respectively. Electrical properties were measured with Pt top electrodes and the typical relative dielectric constant determined by the C-V characteristics is 60-80.


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