Superconducting YBa2Cu3Ox films prepared on YSZ polycrystalline substrates by rf thermal plasma evaporation

1994 ◽  
Vol 9 (5) ◽  
pp. 1089-1097 ◽  
Author(s):  
J. Tsujino ◽  
N. Tatsumi ◽  
Y. Shiohara
Keyword(s):  
Deposition Rate ◽  
Thermal Plasma ◽  
High Deposition Rate ◽  
Practical Application ◽  
Large Area ◽  
Axis Orientation ◽  
Zero Resistance ◽  
Rf Thermal Plasma ◽  
Flexible Metal ◽  
Area Deposition

As-grown YBa2Cu3Ox films prepared on single crystal (100)MgO substrates by rf thermal plasma evaporation have the advantages of a high deposition rate of 730 nm/min, a large area deposition over 300 cm2, and a high Jc of 6.8 × 105 A/cm2 (77 K, O T), as reported in previous papers.1,2 We report in this paper about the preparation of YBa2Cu3Ox films on yttria-stabilized zirconia (YSZ) polycrystalline substrates for a practical application using this technique to synthesize these films on flexible (metal or flexible polycrystal) substrates. Films prepared on YSZ polycrystalline substrates grew with a c-axis orientation at a relatively high deposition rate and exhibited a zero resistance temperature (TcO) of 88 K and a critical current density Jc of 3500 A/cm2 (77 K, O T). Films prepared on flexible YSZ polycrystalline tapes with a length of 100 mm were also grown with a c-axis orientation and exhibited TcO) over 77 K.

Deposition Conditions for Large Area PECVD of Amorphous Silicon

1997 ◽  
Vol 467 ◽  
Author(s):  
J. Kuske ◽  
U. Stephan ◽  
W. Nowak ◽  
S. Röhlecke ◽  
A. Kottwitz
Keyword(s):  
Film Thickness ◽  
Amorphous Silicon ◽  
Deposition Rate ◽  
Excitation Frequency ◽  
Input Power ◽  
High Deposition Rate ◽  
Large Area ◽  
Deposition Parameters ◽  
Plate Size ◽  
Area Deposition

ABSTRACTThe production of amorphous silicon devices usually requires large area, high-deposition-rate plasma reactors. Non-uniformity of the film thickness at high power and deposition rate is found to be an important factor for large area deposition.Increasing the radio frequency from the conventional 13.56 MHz up to VHF has demonstrated advantages for the deposition of a-Si:H films, including higher deposition rates and lower particle generation. The use of VHF for large area deposition leads to the generation of standing waves and evanescent waveguide modes at the electrode surface and on the power feeding lines. Thereby increasing the non-uniformity of the film thickness. The uniformity of the film thickness for an excitation frequency strongly depends on the deposition parameters e.g. pressure, input power, silane flow and the value of load impedances. With increasing exciting frequencies the range of deposition parameters for obtaining uniform films narrows.Subsequently it is shown that for a large-area plasma-box reactor (500 × 600 mm2 plate size) with a double-sided RF electrode, the non-uniformity of the film decreases due to a homoge-neization of the electrode voltage distribution by using multiple power supplies and load impedances on the end of the RF electrode. The uniformity errors decrease from ±20% to ±2.4% (27.12MHz) and from ±40% to ±5.9% (54.24MHz). Experimental results of the film uniformity will be discussed in dependence on excitation frequencies and the deposition parameters.

Problems of Power Feeding in Large Area PECVD of Amorphous Silicon

1999 ◽  
Vol 557 ◽  
Author(s):  
U. Stephan ◽  
J. Kuske ◽  
H. Grüger ◽  
A. Kottwitz
Keyword(s):  
Amorphous Silicon ◽  
Deposition Rate ◽  
Standing Waves ◽  
Plasma Source ◽  
High Deposition Rate ◽  
Plasma Reactors ◽  
Power Losses ◽  
Large Area ◽  
Power Coupling ◽  
Reactor Types

AbstractThe production of amorphous silicon, e.g. for solar cells, requires large area, high-deposition rate plasma reactors. Increasing the radio frequency from the conventional 13.56MHz up to VHF has demonstrated higher deposition and etch rates and lower particle generation, a reduced ion bombardement and lower breakdown, process and bias voltages.But otherwise the use of VHF leads to some problems. The non-uniformity of deposition rate increase due to the generation of standing waves (TEM wave) and evanescent waveguide modes (TE waves) at the electrode surface.Increasing the frequency and/or the deposition area the plasma impedance, the capacitic stray impedance of the RF electrode and other parasitic capacitive impedances decrease. Increasing the frequency and/or the RF power, the phase angle of the discharge and of the impedance at every point at the lines between the RF matching network an the RF electrode tends more and more towards -90°. This results in increasing currents and standing waves with extremly high local current maximas. Increasing resistances of lines and contacts due to the skin effect and loss-caused heating up of the lines the power losses increase extremely, up to 90% and more. In spite of the increasing of the coupled power, the plasma power does not increase. Thermal destructions of the lines due to extreme expansion or melting are possible.Some solutions to reduce the non-uniformity of the deposition rate like multipower feeding, central backside power feeding, electrode segmentation, use of load impedances, published in former publications, will be discussed in connection with several reactor types (coaxial, large area, long plasma source) in view of the efficiency of power coupling and the practical realization. Solutions to minimize the power losses at the lines will be presented.

Low Temperature Preparation of y‐bA‐cU‐0 Films by Omcvd

1989 ◽  
Vol 169 ◽  
Author(s):  
Taiji Tsuruoka ◽  
Ryodo Kawasaki ◽  
Hitoshi Abe ◽  
Susumu Shibata
Keyword(s):  
Low Temperature ◽  
Deposition Rate ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
X Ray ◽  
Low Temperature Preparation ◽  
Zero Resistance ◽  
Diffraction Patterns ◽  
Temperature Preparation

AbstractBy using N2O for oxygen source, Y‐Ba‐Cu‐O films prepared at 650” C on the SrTiO3 substrates showed zero resistance at 79K. The deposition rate of Y‐Ba‐Cu‐0 films on MgO(l00) substrates by using N2O gas was nearly half of that using 02 gas. X‐ray diffraction patterns of Y‐Ba‐Cu‐0 films grown on SrTiO3(100) and MgO(l00) substrates indicate c‐axis orientation.

High-Rate PECVD of Low Defect Density a-Si:H on Large Areas

1997 ◽  
Vol 467 ◽  
Author(s):  
S. Röhlecke ◽  
O. Steinke ◽  
F. Schade ◽  
F. Stahr ◽  
M. Albert ◽  
...  
Keyword(s):  
Deposition Rate ◽  
Defect Density ◽  
Plasma Reactor ◽  
High Rate ◽  
Limiting Factors ◽  
High Deposition Rate ◽  
Large Area ◽  
Particle Generation ◽  
Wide Range ◽  
Deposition Processes

ABSTRACTIndustrial production of amorphous silicon solar cells, photoreceptors and several opto-electronic devices requires large area, high-deposition-rate plasma reactors and deposition processes. Non-uniformity of die film thickness and particle generation at high power densities as well as the deposition rate are found to be important limiting factors in large area PECVD.The deposition was performed in a capacitively-coupled coaxial diode rf glow discharge with large areas (1000 cm2 and 2000 cm2) at 13.56 MHz and 27.12 MHz. We studied the particle generation in the plasma reactor over a wide range of silane concentration (20 % to 100 %) in the SiH4/He mixture. We will present the opto-electronic properties of a-Si:H films and the influence of the substrate bias. The films are characterized by dark- and photoconductivity and by PDS.It was confirmed through this study that helium dilution is effective in the suppression of powder growth for high-rate deposition up to 18 μm/hr. Special attention was paid to the optimization of reactor design and plasma conditions for the deposition of low density of states a-Si:H (∼1016 cm−3) at deposition rates of up to 18 μm/hr. Darkconductivity was 10−9 S/cm and photoconductivity was about 5.10−4 S/cm.

Transparent Conducting Oxide Films for Various Applications: A Review

2018 ◽  
Vol 53 (1) ◽  
pp. 79-89 ◽  
Author(s):  
Rakesh A. Afre ◽  
Nallin Sharma ◽  
Maheshwar Sharon ◽  
Madhuri Sharon
Keyword(s):  
Transparent Conducting Oxide ◽  
High Deposition Rate ◽  
Large Area ◽  
Conducting Oxides ◽  
Transparent Conducting ◽  
Impurity Doped ◽  
Flexible Solar Cell ◽  
P Type ◽  
Area Deposition ◽  
Deposition Techniques

Abstract This review encompasses properties and applications of polycrystalline or amorphous, Transparent Conducting Oxides (TCO) semiconductors. Coexistence of electrical conductivity and optical transparency in TCO depends on the nature, number and atomic arrangements of metal cations in oxides, on the resident morphology and presence of intrinsic or introduced defects. Therefore, TCO semiconductors that are impurity-doped as well as the ternary compounds and multi-component oxides consisting of combinations are discussed. Expanding use of TCO is endangered by scarcity, cost of In, fragility of glass, limited transparency to visible light, instability above >200 °C, non-flexible for application of flexible solar cell; thus driving search for alternatives such as graphene or CNT, that are more stable under acidic, alkaline, oxidizing, reducing and elevated temperature. There are reasons to conclude that there is need to develop large area deposition techniques to produce TCO films with high deposition rate. TCOs are mostly n-type semiconductors, but p-type are also being researched

Study of Large Area a-Si:H and nc-Si:H Based Multijunction Solar Cells and Materials

2008 ◽  
Vol 1066 ◽  
Author(s):  
Xixiang Xu ◽  
Baojie Yan ◽  
Dave Beglau ◽  
Yang Li ◽  
Greg DeMaggio ◽  
...  
Keyword(s):  
Solar Cells ◽  
Deposition Rate ◽  
Plasma Deposition ◽  
Nanocrystalline Silicon ◽  
High Rate ◽  
High Deposition Rate ◽  
Large Area ◽  
Very High Frequency ◽  
Spatial Uniformity ◽  
Double Junction

ABSTRACTSolar cells based on hydrogenated nanocrystalline silicon (nc-Si:H) have demonstrated significant improvement in the last few years. From the standpoint of commercial viability, good quality nc-Si:H films must be deposited at a high rate. In this paper, we present the results of our investigations on obtaining high quality nc-Si:H and a-Si:H films and solar cells over large areas using high deposition rate. We have employed the modified very high frequency (MVHF) glow discharge technique to realize high-rate deposition. Modeling studies were conducted to attain good spatial uniformity of electric field over a large area (15”×1”) MVHF cathode for nc-Si:H deposition. A comparative study has been carried out between the RF and MVHF plasma deposited a-Si:H and nc-Si:H single-junction and a-Si:H/nc-Si:H double-junction solar cells. By optimizing the nc-Si:H cell and the tunnel/recombination junctions, we have obtained an initial aperture-area (460 cm2) efficiency of 11.9% for a-Si:H/nc-Si:H double-junction cells using conventional RF (13.56 MHz) plasma deposition. The deposition rate was 3 Å/sec. Results on solar cells made with MVHF will also be presented.

Post-transit Analysis of Transient Photocurrents from High-Deposition-Rate a-Si:H Samples

2003 ◽  
Vol 762 ◽  
Author(s):  
Monica Brinza ◽  
W.M.M. Kessel ◽  
Arno H.M Smets ◽  
M.C.M van de Sanden ◽  
Guy J. Adriaenssens
Keyword(s):  
Amorphous Silicon ◽  
Deposition Rate ◽  
Density Of States ◽  
Thermal Plasma ◽  
Hydrogenated Amorphous Silicon ◽  
High Deposition Rate ◽  
Flight Experiment ◽  
Plasma Technique ◽  
Gap States ◽  
Hydrogenated Amorphous

AbstractAn interpretation of post-transit photocurrents in a time-of-flight experiment in terms of the underlying density of localized gap states in the sample is presented for the case of hydrogenated amorphous silicon cells prepared by the expanding thermal plasma technique. It is pointed out that part of the observed current is not generated by re-emission of trapped photo-generated charge and should, therefore, not be used for density-of-states calculations.

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