In-Situ Preparation and Characterization of Superconducting Thin Films and Related Materials by Mocvd for the Development of Three Terminal Switching Devices

1989 ◽  
Vol 169 ◽  
Author(s):  
R. Singh ◽  
S. Sinha ◽  
J. Narayan
Keyword(s):  
Thin Films ◽  
High Temperature Superconductor ◽  
Chemical Vapor ◽  
Silicon Substrates ◽  
Superconducting Thin Films ◽  
In Situ Preparation ◽  
In Situ Deposition ◽  
Rapid Isothermal Processing

AbstractMetalorganic chemical vapor deposition (MOCVD) has the potential of emerging as a major technique for the fabrication of high temperature superconductor devices. In this paper, we present preliminary results of in-situ deposition of Y-Ba-Cu-0 thin films (Tc = 79K) by rapid isothermal processing assisted MOCVD on BaF2/silicon substrates.

IN-SITU PREPARATION OF YBa2Cu3O7 SUPERCONDUCTING THIN FILMS BY PULSED Nd:YAG LASER DEPOSITION

1992 ◽  
Vol 06 (08) ◽  
pp. 477-483 ◽  
Author(s):  
QINGXIN SU ◽  
SHIFA XU ◽  
DAFU CUI ◽  
HUIBIN LU ◽  
YONGJUN TIAN ◽  
...  
Keyword(s):  
Thin Films ◽  
Substrate Temperature ◽  
Nd:Yag Laser ◽  
Ac Susceptibility ◽  
Substrate Surface ◽  
Zero Magnetic Field ◽  
Superconducting Thin Films ◽  
In Situ Preparation ◽  
Zero Resistance

High-T c superconducting thin films of YBa 2 Cu 3 O 7 were grown in-situ on (100) SrTiO 3 substrates by Nedymium:yttrium aluminum garnet [Nd:YAG] laser ablation. The effects of the substrate temperature on the transition temperature, microcrystalline structure and surface morphology of the films were discussed. Best results were obtained in the 730°–770°C range. X-ray diffraction analysis showed that these films were highly c-oriented with the c-axis perpendicular to the substrate surface. At the optimum substrate temperature, a very smooth morphology with only a few small particles were observed by scanning electron microscopy. The zero resistance temperature of these films were ≥ 90 K with a narrow transition width and the ac susceptibility measurement also gave the same result. The highest critical current density obtained at 77 K and zero magnetic field was 3.8 × 106 A/cm 2.

In‐Situ Fabrication of YBa2Cu3O7‐x Superconducting Thin Films Directly on Silicon Substrates with Tc0 > 77K

1989 ◽  
Vol 169 ◽  
Author(s):  
C. B. Lee ◽  
R. K. Singh ◽  
S. Sharan ◽  
A. K. Singh ◽  
P. Tiwari ◽  
...  
Keyword(s):  
Thin Films ◽  
Laser Pulses ◽  
Superconducting Film ◽  
Laser Evaporation ◽  
Silicon Substrates ◽  
Superconducting Thin Films ◽  
Si Substrates ◽  
In Situ Fabrication ◽  
Substrate Temperatures

AbstractWe report in‐situ fabrication of c‐axis textured YBa2Cu3O7‐x superconducting thin films with Tco > 77K on unbuffered silicon substrates by the biased pulsed laser evaporation (PLE) technique in the temperature range of 550‐650°C. At substrate temperatures below 550°C, no c‐axis texturing of the superconducting film was observed. The YBa2Cu3O7‐x superconducting films were fabricated by ablating a bulk YBa2Cu3O7 target by a XeCl excimer laser (λ = 308 nm, τ = 45 × 10‐9 sec) in a chamber maintained at an oxygen pressure of 0.2 torr . The thickness of the films was varied from 0.3 to 0.5 nm depending on the number of laser pulses. Extensive diffusion was observed in thin films deposited at substrate temperatures above 550°C. However, microstructurally, with increase in the substrate temperature the films exhibited larger grain size and greater degree of c‐axis texturing (measured by the ratio of the (005) and (110) X‐ray diffraction peaks). This was found to give rise to better superconducting properties with Tco exceeding 77 K for YBa2Cu3O7‐x films deposited on Si substrates at 650°C.

In-Situ Preparation of Y-Ba-Cu-O Thin Films Using Mass-Spectrometer Rate Control and Atomic Oxygen

1992 ◽  
Vol 275 ◽  
Author(s):  
H. Ohlsén ◽  
M. Ottosson ◽  
J. Hudner ◽  
M. ÖStling ◽  
L. Stolt ◽  
...  
Keyword(s):  
Thin Films ◽  
Mass Spectrometer ◽  
Rate Control ◽  
Atomic Oxygen ◽  
Film Structure ◽  
Rocking Curve ◽  
In Situ Preparation ◽  
Layer Structures

ABSTRACTThin films of YBCO were prepared using a mass-spectrometer controlled coevapora-tion/MBE process with atomic oxygen. Under the conditions of low pressure, necessary for mass-spectrometer rate control, it is shown that an atomic oxygen beam source can be utilized in order to grow high quality thin films of YBCO as well as multi-layer structures involving YBCO and Y2O3. Values of Tc = 88.5 K and Jc = 6–106 A/cm2 at 77 K were determined for a strip with a width of 10 μm of YBCO deposited on a LaAlO3 substrate. Film structure is analyzed by XRD and rocking curve measurements. Magnetic characterization of films and multi-layer structures are reported.

Preparation and Characterization of Chromium Containing amorphous Hydrogenated Carbon Films (A-C:H/Cr)

1995 ◽  
Vol 388 ◽  
Author(s):  
R. Gampp ◽  
P. Gantenbein ◽  
P. Oelhafen
Keyword(s):  
Chromium Carbide ◽  
Photoelectron Spectroscopy ◽  
Chemical Vapor ◽  
Carbon Films ◽  
Rf Plasma ◽  
Silicon Substrates ◽  
Amorphous Hydrogenated Carbon ◽  
High Chemical Stability

AbstractChromium containing amorphous hydrogenated carbon films (a-C:H/Cr) were prepared in a process that combines rf plasma activated chemical vapor deposition of methane and magnetron sputtering of a chromium target. During the deposition the silicon substrates were kept at 200°C and dc biased at -200 V in order to obtain films with high chemical stability which is required for the application as solar selective surfaces. the films with different Cr concentrations (5 to 49 at.%) were characterized by in situ x-ray photoelectron spectroscopy (XPS). Up to 40 at.%, chromium proves to be built into the cermet-like films in the form of chromium carbide clusters. above 40 at.%, chromium is partly metallic. a modification of the a-C:H matrix in the vicinity of the chromium carbide clusters has been observed.

scholarly journals Propiedades ópticas y estructurales de las películas de óxido de silicio rico en silicio obtenidas por la técnica HFCVD

2019 ◽  
pp. 9-14
Author(s):  
Nora Castillo-Tépox ◽  
José Alberto Luna-López ◽  
José Álvaro David Hernández-De la Luz ◽  
Karim Monfil-Leyva
Keyword(s):  
Thin Films ◽  
Chemical Vapor ◽  
Optical Transmittance ◽  
Silicon Substrates ◽  
Hydrogen Flow ◽  
Optical Energy Band Gap ◽  
Order Of Magnitude ◽  
P Type ◽  
Hot Filament

In this work we present the results of the analysis obtained from the deposit and characterization of thin films of silicon rich oxide (SRO). The films were obtained by hot filament chemical vapor deposition (HFCVD) technique, such films were deposited on silicon substrates p-type. The deposit of thin films was realized considering different distances from source to substrate (DFS) which were 3, 4, 5 and 6 mm. The quantity of precursors (SiO2) was controlled by the distance from the filament to the source, which was 6 mm for this work, the filament was held at 2000°C. A constant 3-minute deposit time was maintained, and the hydrogen flow level was 10 sccm. The films thickness was obtained by using the profilometry technique, the thickness range was from 200 to 600 nm. The vibrational molecular modes of the SRO films were obtained by Fourier Transform Infrared Spectroscopy (FTIR). The films of 3 mm DFS exhibit an optical transmittance of 90%. The optical energy band gap of the thin films varies from 2.2 to 3.3 eV. When an annealing process at 1000°C was carried out for one hour, the SRO films increase their photoluminescence by an order of magnitude approximately.

Sign in / Sign up

Export Citation Format

Share Document