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.

Large Grain Size and High Deposition Rate for Microcrystalline Silicon Prepared by VHF-GD

1994 ◽  
Vol 358 ◽  
Author(s):  
P. Hapke ◽  
F. Finger ◽  
M. Luysberg ◽  
R. Carius ◽  
H. Wagner
Keyword(s):  
Grain Size ◽  
Deposition Rate ◽  
High Frequency ◽  
Excitation Frequency ◽  
Chemical Vapour ◽  
High Deposition Rate ◽  
Very High Frequency ◽  
Deposition Parameters ◽  
Plasma Excitation ◽  
Very High

ABSTRACTThe growth mechanism and material properties of -type µc-Si:H prepared with plasma enhanced chemical vapour deposition in the very high frequency range is investigated. By increasing the plasma excitation frequency the grain size, deposition rate and Hall mobility can be simultaneously increased without having to adjust other deposition parameters in particular the temperature. This effect is explained by an enhanced selective etching of amorphous tissue and grain boundary regions together with a sufficient supply of growth species at high frequency plasmas.

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.

VHF Large Area Plasma Processing on Moving Substrats

2001 ◽  
Vol 664 ◽  
Author(s):  
J. Kuske ◽  
U. Stephan ◽  
R. Terasa ◽  
H. Brechtel ◽  
A. Kottwitz
Keyword(s):  
Deposition Rate ◽  
Optical Emission ◽  
Plasma Source ◽  
Deposition Process ◽  
Small Scale ◽  
High Deposition Rate ◽  
Plasma Reactors ◽  
Large Area ◽  
Particle Generation ◽  
Deposition Parameters

ABSTRACTThe production of amorphous and microcrystalline silicon, e.g. for solar cells, requires large area, high-deposition rate plasma reactors. Increasing the 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 the use of VHF for large area systems leads to some problems. The non-uniformity of deposition rate increases due to the generation of standing waves and evanescent waveguide modes at the electrode surface. One possibility to process large area substrates is the use of a one-dimensional extended, homogeneous plasma source in combination with a moving substrate. The requirements, which result from the deposition process and from the RF-engineering, corresponds with the developed plasma source, using deposition frequencies in the VHF-range (50-100 MHz), almost perfectly.Using a source of 550mm length experiments were done with 81.36MHz at RF power densities of 70-180mW/cm2, silane/ hydrogen pressures of 5-30Pa and flow rates of 10-300sccm. The measured potential distribution error was ±2%. Optical emission spectroscopy delivered discharge intensity errors of ±3-10%. Deposition rates up to 20µm/h for amorphous silicon (60Å/s) and film thickness inhomogenities less than ±5% were achieved (with an area of the moved substrate of 30cm–30cm). Experimental results of the film properties will be discussed in relation to the deposition parameters and compared with complementary experiments, carried out on a small scale equipment with excitation frequencies up to 165 MHz.

(111) Monocrystalline Nickel Films

1972 ◽  
Vol 30 ◽  
pp. 512-513
Author(s):  
T.E. Pratt ◽  
R.W. Vook
Keyword(s):  
Film Thickness ◽  
Deposition Rate ◽  
Room Temperature ◽  
Narrow Range ◽  
High Vacuum ◽  
Residual Pressure ◽  
Temperature Dependent ◽  
Deposition Parameters ◽  
Transmission Electron ◽  
Substrate Temperatures

(111) oriented thin monocrystalline Ni films have been prepared by vacuum evaporation and examined by transmission electron microscopy and electron diffraction. In high vacuum, at room temperature, a layer of NaCl was first evaporated onto a freshly air-cleaved muscovite substrate clamped to a copper block with attached heater and thermocouple. Then, at various substrate temperatures, with other parameters held within a narrow range, Ni was evaporated from a tungsten filament. It had been shown previously that similar procedures would yield monocrystalline films of CU, Ag, and Au.For the films examined with respect to temperature dependent effects, typical deposition parameters were: Ni film thickness, 500-800 A; Ni deposition rate, 10 A/sec.; residual pressure, 10-6 torr; NaCl film thickness, 250 A; and NaCl deposition rate, 10 A/sec. Some additional evaporations involved higher deposition rates and lower film thicknesses.Monocrystalline films were obtained with substrate temperatures above 500° C. Below 450° C, the films were polycrystalline with a strong (111) preferred orientation.

Excitation Frequency Effects on Stabilized Efficiency of Large-Area Amorphous Silicon Solar Cells Using Flexible Plastic Film Substrate

2003 ◽  
Vol 42 (Part 2, No. 11A) ◽  
pp. L1312-L1314 ◽  
Author(s):  
Akihiro Takano ◽  
Masayuki Tanda ◽  
Makoto Shimosawa ◽  
Takehito Wada ◽  
Tomoyoshi Kamoshita
Keyword(s):  
Solar Cells ◽  
Amorphous Silicon ◽  
Excitation Frequency ◽  
Silicon Solar Cells ◽  
Plastic Film ◽  
Large Area ◽  
Frequency Effects ◽  
Film Substrate

Single Wafer Amorphous Silicon Process Evaluation

1997 ◽  
Vol 467 ◽  
Author(s):  
David O'Meara ◽  
Chow Ling Chang ◽  
Roc Blumenthal ◽  
Rama I. Hegde ◽  
Lata Prabhu ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Morphology ◽  
Amorphous Silicon ◽  
Deposition Rate ◽  
Cross Sections ◽  
Growth Conditions ◽  
Degree Of Crystallinity ◽  
Deposition Parameters ◽  
Before And After ◽  
Production Requirement

ABSTRACTSingle wafer amorphous silicon deposition was characterized through process modeling and film characterization for application in semiconductor production. DOE methodology was used to determine the main deposition parameters, and the responses were limited to device production requirement properties of surface roughness, deposition rate and degree of crystallinity of the as-deposited film. The data trends and models show that deposition temperature and silane flow are the main factors. Increasing either or both factor increases the deposition rate and the surface roughness. The surface morphology, evaluated by AFM, SEM and TEM, was found to be rougher at extreme growth conditions than the poly crystalline film formed after anneal. The as-deposited surface morphology was not a result of pre-anneal crystal formations as determined by TEM cross sections of samples before and after anneal. Lack of crystalinity is important for impurity diffusion considerations. Device application of the single wafer a-Si process will be a compromise between growth rate (and associated throughput) and surface roughness that can be tolerated.

Large-area Deposition of Amorphous Silicon Alloys Using a Roll-to-roll Operation

2005 ◽  
Vol 870 ◽  
Author(s):  
Subhendu Guha ◽  
Jeffrey Yang
Keyword(s):  
Amorphous Silicon ◽  
Triple Junction ◽  
Stainless Steel Substrate ◽  
Steel Substrate ◽  
Chemical Vapor ◽  
Large Area ◽  
Silicon Alloys ◽  
Roll To Roll ◽  
Layer Structures ◽  
Area Deposition

AbstractLarge-area deposition of thin-film amorphous silicon alloy triple-junction solar cells on lightweight and flexible stainless steel substrate is described. The proprietary roll-to-roll operation enables continuous depositions of sophisticated multi-layer structures. The deposition methods include sputtering and plasma-enhanced chemical vapor depositions. Spectrumsplitting triple-junction solar cell design, manufacturing processes, and product applications are presented.

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