High Deposition Rate a-Si:H for the Flat Panel Display Industry

1996 ◽  
Vol 420 ◽  
Author(s):  
J. Hautala ◽  
Z. Saleh ◽  
J. F. M. Westendorp ◽  
H. Meiling ◽  
S. Sherman ◽  
...  
Keyword(s):  
Deposition Rate ◽  
Defect Density ◽  
Dark Conductivity ◽  
Critical Conditions ◽  
Process Conditions ◽  
High Deposition Rate ◽  
Flat Panel Display ◽  
Deposition Rates ◽  
Powder Formation ◽  
And Control

AbstractHigh deposition rates and good quality electrical properties and thickness uniformities over large areas are required for all three films (SiNx, a-Si:H and n+a-Si:H) composing the thin film transistors (TFTs) for the AMLCD industry, while maintaining high tool up-time and low particle formation. Generally these conditions have been achieved for most single-panel multichamber PECVD systems; however, it has become increasingly apparent that a compromise is drawn between the TFT mobility and the deposition rate of the a-Si:H layer. Thus it becomes essential to clearly assess the industry requirements for both deposition rates as well as TFT performance for the different device structures used for AMLCDs, and to discover and control these underlying material properties.The TEL VHF (40/60 MHz) PECVD system produces high quality, low defect density a- Si:H at deposition rates exceeding 1500 Å/min when analyzed by FTIR, CPM, photo and dark conductivity. Even though the low deposition rate a-Si:H exhibits very similar bulk properties, higher mobility TFTs are produced with a-Si:H deposited at lower RF power. Having both a high ion flux and low ion energy in the SiH4 discharge are likely the most critical conditions for controlling the a-Si:H quality and thus the TFT mobility. Increasing the RF frequency enhances both of these effects, as well as provides a higher deposition rate for a given power density and a higher power threshold for particle/powder formation. For these reasons it is likely a 40/60 MHz plasma will produce better performing TFTs for a given deposition rate when compared with a conventional 13.56 MIHz system. Other process conditions such as diluting the SiH4 in H2 or Ar also seem to play an important role in the optoelectronic properties of the a-Si:H film and ultimately the TFT performance.

High Deposition Rate a-Si:H for the Flat Panel Display Industry

1996 ◽  
Vol 424 ◽  
Author(s):  
J. Hautala ◽  
Z. Saleh ◽  
J. F. M. Westendorp ◽  
H. Meiling ◽  
S. Sherman ◽  
...  
Keyword(s):  
Deposition Rate ◽  
Defect Density ◽  
Dark Conductivity ◽  
Critical Conditions ◽  
Process Conditions ◽  
High Deposition Rate ◽  
Flat Panel Display ◽  
Deposition Rates ◽  
Powder Formation ◽  
And Control

AbstractHigh deposition rates and good quality electrical properties and thickness uniformities over large areas are required for all three films (SiNx, a-Si:H and n+ a-Si:H) composing the thin film transistors (TFTs) for the AMLCD industry, while maintaining high tool up-time and low particle formation. Generally these conditions have been achieved for most single-panel multichamber PECVD systems; however, it has become increasingly apparent that a compromise is drawn between the TFT mobility and the deposition rate of the a-Si:H layer. Thus it becomes essential to clearly assess the industry requirements for both deposition rates as well as TFT performance for the different device structures used for AMLCDs, and to discover and control these underlying material properties.The TEL VHF (40/60 MHz) PECVD system produces high quality, low defect density a- Si:H at deposition rates exceeding 1500 Å/min when analyzed by FTIR, CPM, photo and dark conductivity. Even though the low deposition rate a-Si:H exhibits very similar bulk properties, higher mobility TFTs are produced with a-Si:H deposited at lower RF power. Having both a high ion flux and low ion energy in the SiH4 discharge are likely the most critical conditions for controlling the a-Si:H quality and thus the TFT mobility. Increasing the RF frequency enhances both of these effects, as well as provides a higher deposition rate for a given power density and a higher power threshold for particle/powder formation. For these reasons it is likely a 40/60 MHz plasma will produce better performing TFTs for a given deposition rate when compared with a conventional 13.56 MHz system. Other process conditions such as diluting the SiH4 in H2 or Ar also seem to play an important role in the optoelectronic properties of the a-Si:H film and ultimately the TFT performance.

High Deposition Rate Pecvd Processes For Next Generation Tft-Lcds

1994 ◽  
Vol 345 ◽  
Author(s):  
J. F. M. Westendorp ◽  
H. Meiling ◽  
J. D. Pollock ◽  
D. W. Berrian ◽  
A. H. Laflamme ◽  
...  
Keyword(s):  
Glow Discharge ◽  
Deposition Rate ◽  
Rf Discharge ◽  
High Yield ◽  
High Deposition Rate ◽  
Very High Frequency ◽  
Doped Semiconductors ◽  
Deposition Rates ◽  
Powder Formation ◽  
High Production

AbstractThe demand for lower cost per panel in TFT-LCD production is driving the PECVD market to deposition systems that combine high throughput and uptime with high yield. Today it is generally believed that a multichamber system that combines a number of single-panel deposition chambers is the best way to achieve these goals.For these PECVD systems to be economical, the deposition rate of a-Si:H, SiNx and SiO2 has to be in the 1200–1500 Å/min range. In 13.56 MHz parallel-plate glow discharge systems SiNx and SiO2 deposition rates exceeding 1500 Å/min are commonly achieved, whereas the deposition rate of a-Si:H is limited to 100–200 Å/min due to powder formation. Over the last 5 years significant progress has been made to increase the deposition rate of a-Si:H. Methods include the use of very-high-frequency glow discharge (VHF-GD) and pulsing of the rf discharge. However, substrate sizes never exceeded 100mm×100mm.We have developed a multichamber PECVD system for TFT-LCD production where VHFGD is used to obtain uniform high deposition rates for (doped) semiconductors and insulators, such as a-Si:H, n+ a-Si:H, SiNx and SiO2 over areas as large as 470mm×370mm. Even at deposition rates well above 1200 Å/min hydrogen in a-Si:H is exclusively bound as monohydride. The optoelectronic properties of the films are at least as good as those of their 13.56 MHz counterparts and thus good-quality TFTs can be obtained. At the same time the number of added particles is low allowing for high production yields.

Impact of Deposition Rate on the Structural and Magnetic Properties of Sputtered Ni/Cu Multilayer Thin Films

2017 ◽  
Vol 73 (1) ◽  
pp. 85-90 ◽  
Author(s):  
Ali Karpuz ◽  
Salih Colmekci ◽  
Hakan Kockar ◽  
Hilal Kuru ◽  
Mehmet Uckun
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Deposition Rate ◽  
High Rate ◽  
Cubic Phase ◽  
High Deposition Rate ◽  
Multilayer Thin Films ◽  
Face Centered Cubic ◽  
Deposition Rates ◽  
Cu Films

AbstractThe structural and corresponding magnetic properties of Ni/Cu films sputtered at low and high deposition rates were investigated as there is a limited number of related studies in this field. 5[Ni(10 nm)/Cu(30 nm)] multilayer thin films were deposited using two DC sputtering sources at low (0.02 nm/s) and high (0.10 nm/s) deposition rates of Ni layers. A face centered cubic phase was detected for both films. The surface of the film sputtered at the low deposition rate has a lot of micro-grains distributed uniformly and with sizes from 0.1 to 0.4 μm. Also, it has a vertical acicular morphology. At high deposition rate, the number of micro-grains considerably decreased, and some of their sizes increased up to 1 μm. The surface of the Ni/Cu multilayer deposited at the low rate has a relatively more grainy and rugged structure, whereas the surface of the film deposited at the high rate has a relatively larger lateral size of surface grains with a relatively fine morphology. Saturation magnetisation, Ms, values were 90 and 138 emu/cm3 for deposition rates of 0.02 and 0.10 nm/s, respectively. Remanence, Mr, values were also found to be 48 and 71 emu/cm3 for the low and high deposition rates, respectively. The coercivity, Hc, values were 46 and 65 Oe for the low and high Ni deposition rates, respectively. The changes in the film surfaces provoked the changes in the Hc values. The Ms, Mr, and Hc values of the 5[Ni(10 nm)/Cu(30 nm)] films can be adjusted considering the surface morphologies and film contents caused by the different Ni deposition rates.

Defect Density of a-Si: H(B) Prepared at High Deposition Rate with Triethylboron

1992 ◽  
Vol 134 (1) ◽  
pp. 167-181 ◽  
Author(s):  
J. Schmal ◽  
G. Kluge ◽  
A. Kottwitz ◽  
R. Bindemann ◽  
K. Schade
Keyword(s):  
Deposition Rate ◽  
Defect Density ◽  
High Deposition Rate

Electronic transport study of high deposition rate HWCVD a-Si:H by the microwavephotomixing technique

2001 ◽  
Vol 664 ◽  
Author(s):  
S.R. Sheng ◽  
R. Braunstein ◽  
B.P. Nelson ◽  
Y. Xu
Keyword(s):  
Substrate Temperature ◽  
Deposition Rate ◽  
Flow Rate ◽  
Electronic Transport ◽  
High Deposition Rate ◽  
Deposition Pressure ◽  
Film Properties ◽  
High Quality ◽  
Deposition Rates ◽  
Potential Fluctuations

ABSTRACTThe electronic transport properties of high deposition rate a-Si:H films prepared by HWCVD have been investigated in detail by employing the microwave photomixing technique. The high deposition rates (up to 1 µm/min.) were achieved by adding a second filament, increasing deposition pressure, silane flow rate, and decreasing filament-to-substrate distance. The effect of the deposition rate on the resultant film properties with respect to the substrate temperature, deposition pressure and silane flow rate was studied. It was found that the film transport properties do not change monotonically with increasing deposition rate. The photoconductivity peaks at ∼70-90 Å/s, where both the drift mobility and lifetime peak, consistent with the deposition rate dependence of the range and depth of the potential fluctuations. High quality, such as a photoconductivity-to-dark-conductivity ratio of ∼105 and nearly constant low charged defect density, can be maintained at deposition rates up to ∼150 Å/s, beyond which the film properties deteriorate rapidly as a result of an enhanced effect of the long-range potential fluctuations due to a considerable increase in the concentration of the charged defects. Our present results indicate that medium silane flow rate, low pressure, and higher substrate temperature are generally required to maintain high quality films at high deposition rates.

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.

Hydrogenated Amorphous Silicon Grown by Hot-Wire CVD at Deposition Rates up to 1 µm/minute

2000 ◽  
Vol 609 ◽  
Author(s):  
Brent P. Nelson ◽  
Yueqin Xu ◽  
A. Harv Mahan ◽  
D.L. Williamson ◽  
R.S. Crandal
Keyword(s):  
Amorphous Silicon ◽  
Deposition Rate ◽  
Defect Density ◽  
Hydrogenated Amorphous Silicon ◽  
Conductivity Ratio ◽  
Hot Wire ◽  
Single Filament ◽  
Deposition Rates ◽  
X Ray ◽  
Hydrogenated Amorphous

ABSTRACTWe grow hydrogenated amorphous-silicon (a-Si:H) by the hot-wire chemical vapor deposition (HWCVD) technique. In our standard tube-reactor we use a single filament, centered 5 cm below the substrate and obtain deposition rates up to 20 Å/s. However, by adding a second filament, and decreasing the filament-to-substrate distance, we are able to grow a-Si:H at deposition rates exceeding 167 Å/s (1 µm/min). We find the deposition rate increases with increasing deposition pressure, silane flow rate, and filament current and decreasing filament-tosubstrate distance. There are significant interactions among these parameters that require optimization to grow films of optimal quality for a desired deposition rate. Using our best conditions, we are able to maintain an AM1.5 photoconductivity-to-dark-conductivity ratio of 105 at deposition rates up to 130 Å/s, beyond which the conductivity ratio decreases. Other electronic properties decrease more rapidly with increasing deposition rate, including the ambipolar diffusion length, Urbach energy, and the as-grown defect density. Measurements of void density by small-angle X-ray scattering (SAXS) reveal an increase by well over an order of magnitude when going from one to two filaments. However, both Raman and X-ray diffraction (XRD) measurements show no change in film structure with increasing deposition rates up to 144 Å/s, and atomic force microscopy (AFM) reveals little change in topology.

Computational Study of SiC Halide Chemical Vapor Deposition System

2007 ◽  
Author(s):  
Rong Wang ◽  
Ronghui Ma ◽  
Govindhan Dhanaraj ◽  
Yi Chen ◽  
Michael Dudley
Keyword(s):  
Electrical Properties ◽  
Defect Density ◽  
Computational Study ◽  
Substrate Surface ◽  
High Surface ◽  
Processing Parameters ◽  
Surface Reactivity ◽  
High Deposition Rate ◽  
Deposition Rates ◽  
Wide Range

Halide CVD (HCVD) is recently employed to grow SiC epitaxial layers using SiCl4/C3H8/H2 mixtures in an effort to achieve high deposition rates. The introduction of the chlorinated species allows the formation of more stable species SiCl2 while maintaining high surface reactivity, thus avoiding the silicon gas phase nucleation that has been widely reported in conventional CVD process using SiH4/C3H8/H2. However, the difficulties in reducing defect density and controlling the electrical properties of the material present a significant technical obstacle for HCVD of SiC. In experimental growth, the electrical properties, defect densities and the growth rate of as-deposited SiC epitaxial films are, to a large extent, determined by processing parameters including temperature, pressure, flow rates of precursors and carrier gas. Optimization of growth conditions provides the opportunity to engineer films with desired film properties and qualities at high deposition rate but requires in-depth understanding the deposition process. In this study, we performed computational study to investigate the effects of main processing parameters in HCVD process on film growth. Numerical experiments were performed over a wide range of operational parameters to provide information on distributions of gas velocity, temperature, and chemical species’ concentrations in the reactor as well as the deposition rates on the substrate surface. Simulations were also carried out to address hot zone design and operational conditions.

Preparation of a-Si:H and a-SiGe:H I-Layers for Nip Solar Cells at High Deposition Rates Using a Very High Frequency Technique

1998 ◽  
Vol 507 ◽  
Author(s):  
S.J. Jones ◽  
X. Deng ◽  
T. Liu ◽  
M. Izu
Keyword(s):  
Solar Cells ◽  
Deposition Rate ◽  
High Frequency ◽  
High Efficiency ◽  
High Deposition Rate ◽  
Very High Frequency ◽  
Deposition Rates ◽  
Single Junction ◽  
Layer Deposition ◽  
Very High

ABSTRACTThe 70 MHz Plasma Enhance Chemical Vapor Deposition (PECVD) technique has been tested as a high deposition rate (10 A/s) process for the fabrication of a-Si:H and a-SiGe:H alloy ilayers for high efficiency nip solar cells. As a prelude to multi-junction cell fabrication, the deposition conditions used to make single-junction a-Si:H and a-SiGe:H cells using this Very High Frequency (VHF) method have been varied to optimize the material quality and the cell efficiencies. It was found that the efficiencies and the light stability for a-Si:H single-junction cells can be made to remain relatively constant as the i-layer deposition rate is varied from 1 to 10 Å/s. Also these stable efficiencies are similar to those for cells made at low deposition rates (1 Å/s) using the standard 13.56 MHz PECVD technique. For the a-SiGe:H cells of the same i-layer thickness, use of the VHF technique leads to cells with higher currents and an ability to more easily current match triple-junction cells prepared at high deposition rates which should lead to higher multi-junction efficiencies. Thus, use of this VHF method in the production of large area a- Si:H based multi-junction solar modules will allow for higher i-layer deposition rates, higher manufacturing throughput and reduced module cost.

The Properties of a-SiC:H and a-SiGe:H Films Deposited by 55 kHz PECVD

1999 ◽  
Vol 557 ◽  
Author(s):  
B.G. Budaguan ◽  
A.A. Sherchenkov ◽  
A.E. Berdnikov ◽  
J.W. Metselaar ◽  
A.A. Aivazov
Keyword(s):  
Glow Discharge ◽  
Electronic Properties ◽  
Chemical Reactions ◽  
Defect Density ◽  
Dark Conductivity ◽  
Growth Surface ◽  
Deposition Rates ◽  
Afm Analysis ◽  
Deposition Processes ◽  
Product Defect

AbstractThe deposition processes and the properties of a-SiC:H and a-SiGe:H films in 55 kHz glow discharge were investigated. The analysis of deposition rate and RBS measurements showed that the chemical reactions between SiHn spices and CH4 control the incorporation of C in a-SiC:H films. High deposition rates of a-SiC:H and a-SiGe:H films fabricated by 55 kHz PECVD is caused by the increase of radical fluxes to the growth surface. The specific features of a-SiC:H and a-SiGe:H microstructure were revealed by IR and AFM analysis. In a-SiC:H films the islands of low size were distinguished on the surfaces of large islands. The large variation of the total hydrogen content in a-SiGe:H did not affect the optical bandgap, while the hydrogen related microstructure controlled the electronic properties such as dark conductivity, 11p.r product, defect density and Urbach slope.The results of optoelectronic properties and SW effect measurements of 55 kHz a-SiC:H and a-SiGe:H films demonstrated the increased stability in comparison with a-Si:H.

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