scholarly journals Substrate Sensitivity of the Adhesion and Material Properties of RF-PECVD Amorphous Carbon

1999 ◽  
Vol 558 ◽  
Author(s):  
Shashi Paul ◽  
F.J Clough
Keyword(s):  
Amorphous Carbon ◽  
Material Properties ◽  
Electronic Device ◽  
Substrate Surface ◽  
Chemical Vapour ◽  
Growth Conditions ◽  
Spatial Variations ◽  
Large Area ◽  
Interlayer Dielectric ◽  
Self Bias

ABSTRACTHydrogenated amorphous carbon (a-C:H), deposited by the if-plasma enhanced chemical vapour deposition (rf-PECVD) technique, is a promising material for large area electronic and interlayer dielectric applications. The structural and electronic properties of rf-PECVD a-C:H, deposited at room temperature from CH4/He and CH4/Ar gas mixtures, are shown to be sensitive to the substrate on which the thin film is deposited. The choice of substrate (c-Si or C7059 glass), and the existence and geometrical dimensions of any metallic pattern on the substrate surface, can result in significant spatial variations in the a-C:H adhesion and material properties. The observed effects are attributed to potential variations across the metal patterned substrates which influence the ‘local’ dc self-bias. This leads to spatial variations in the growth conditions and hence material properties. For electronic device and dielectric isolation applications this effect can result in significant variations in operating performance. The nature of the substrate and any overlying metallisation pattern are therefore important considerations.

scholarly journals Correlation of p-doping in CVD Graphene with Substrate Surface Charges

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
S. Goniszewski ◽  
M. Adabi ◽  
O. Shaforost ◽  
S. M. Hanham ◽  
L. Hao ◽  
...  
Keyword(s):  
Contact Angle ◽  
Gate Voltage ◽  
Dirac Point ◽  
Substrate Surface ◽  
Chemical Vapour ◽  
Charge Carrier Density ◽  
Surface Charges ◽  
Large Area ◽  
Cvd Graphene ◽  
Graphene Field Effect Transistor

Abstract Correlations between the level of p-doping exhibited in large area chemical vapour deposition (CVD) graphene field effect transistor structures (gFETs) and residual charges created by a variety of surface treatments to the silicon dioxide (SiO2) substrates prior to CVD graphene transfer are measured. Beginning with graphene on untreated thermal oxidised silicon, a minimum conductivity (σ min ) occurring at gate voltage V g  = 15 V (Dirac Point) is measured. It was found that more aggressive treatments (O2 plasma and UV Ozone treatments) further increase the gate voltage of the Dirac point up to 65 V, corresponding to a significant increase of the level of p-doping displayed in the graphene. An electrowetting model describing the measured relationship between the contact angle (θ) of a water droplet applied to the treated substrate/graphene surface and an effective gate voltage from a surface charge density is proposed to describe biasing of V g at σ min and was found to fit the measurements with multiplication of a correction factor, allowing effective non-destructive approximation of substrate added charge carrier density using contact angle measurements.

Numerical Simulation of Microcrystalline Silicon Growth on Structured Substrate

2006 ◽  
Vol 910 ◽  
Author(s):  
Martin Python ◽  
Evelyne Vallat-Sauvain ◽  
Julien Bailat ◽  
Christophe Ballif ◽  
Arvind Shah
Keyword(s):  
Volume Fraction ◽  
Incidence Angle ◽  
Substrate Surface ◽  
Chemical Vapour ◽  
Growth Conditions ◽  
Microcrystalline Silicon ◽  
Very High Frequency ◽  
High Frequency Plasma ◽  
Frequency Plasma ◽  
Silicon Growth

AbstractThe growth of thin-film silicon close to the amorphous/microcrystalline transition is qualitatively described by a 3D - discrete dynamical growth model on a cubic lattice. The result of this simulation is a representation of the microstructure of the layer as a function of time, i.e. computer-generated animations of growing microcrystalline silicon layers. It permits to follow the evolution of the nucleation and of the growth of the crystalline phase, the surface roughness, the average crystalline volume fraction and the void volume fraction. In these computer simulations, the effects of the substrate surface morphology and of the distribution of particles incidence angle have been studied.Comparison between simulated normal and isotropic incidence on structured substrates indicates that, under microcrystalline growth conditions, shadowing effects lead to the occurrence of cracks in the simulated microstructure. These effects are also evidenced experimentally in the case of μc-Si:H silicon layers deposited by very high frequency plasma-enhanced chemical vapour deposition (VHF-PECVD) on periodic and random nanostructured substrates.

Patterning Organic Fluorescent Molecules with SAM Patterns

2011 ◽  
Vol 1335 ◽  
Author(s):  
Qiong Wu ◽  
Juanyuan Hao ◽  
Shoulei Shi ◽  
Weifeng Wang ◽  
Nan Lu
Keyword(s):  
Organic Molecules ◽  
Low Cost ◽  
Substrate Surface ◽  
Large Area ◽  
Self Assembled Monolayer ◽  
Storage Duration ◽  
Light Emitting ◽  
High Throughput Method ◽  
Self Assembled ◽  
Fluorescent Molecules

ABSTRACTWe report a low-cost and high-throughput method to fabricate large-area light emitting pattern via thermal evaporation of organic molecules on the patterned self-assembled monolayer of homogenous 3-aminopropyltrimethoxysilane. This method is based on the selective deposition of the organic light emitting molecules on the template of self-assembled monolayer (SAM), which is patterned with nanoimprinting lithography. The selectivity can be controlled by adjusting the design of the pattern, the storage duration and the substrate temperature. The deposition selectivity of the molecules may be caused by the different binding energy of the molecules with the SAM and the substrate surface.

Observations on the Growth of YBa2Cu3O7 Thin Films at Very High Laser Fluences

1995 ◽  
Vol 388 ◽  
Author(s):  
Rand R. Biggers. ◽  
M. Grant Norton ◽  
I. Maartense ◽  
T.L. Peterson ◽  
E. K. Moser ◽  
...  
Keyword(s):  
Thin Films ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Organic Chemical ◽  
High Fluences ◽  
Laser Fluences ◽  
High Laser ◽  
High Laser Fluences ◽  
Very High

AbstractThe pulsed-laser deposition (PLD) technique utilizes one of the most energetic beams available to form thin films of the superconducting oxide YBa2Cu3O7 (YBCO). IN this study we examine the growth of YBCO at very high laser fluences (25 to 40 J/cm2); a more typical fluence for PLD would be nearer to 3 J/cm2. the use of high fluences leads to unique film microstructures which, in some cases, appear to be related to the correspondingly higher moveabilities of the adatoms. Films grown on vicinal substrates, using high laser fluences, exhibited well-defined elongated granular morphologies (with excellent transition temperature, Tc, and critical current density, Jc). Films grown on vicinal substrates using off-axis magnetron sputtering, plasma-enhanced metal organic chemical vapor deposition (PE-MOCVD), or PLD at more typical laser fluences showed some similar morphologies, but less well-defined. Under certain growth conditions, using high laser fluences with (001) oriented substrates, the YBCO films can exhibit a mixture of a- and c-axis growth where both crystallographic orientations nucleate on the substrate surface at the same time, and grow in concert. the ratio of a-axis oriented to c-axis oriented grains is strongly affected by the pulse repetition rate of the laser.

Optimisation of Nickel Aluminising by CVD

2012 ◽  
Vol 323-325 ◽  
pp. 367-372 ◽  
Author(s):  
Patrick J. Masset ◽  
Agnieszka Bogusz ◽  
Jan Sieniawski ◽  
Bartek Wierzba ◽  
Katarzyna Tkacz-Śmiech
Keyword(s):  
Substrate Surface ◽  
Chemical Vapour ◽  
Aluminium Chloride ◽  
Aluminium Content ◽  
Surface Boundary ◽  
Essential Information ◽  
Nial Phase ◽  
Partial Pressures ◽  
State Diffusion ◽  
Surface Boundary Condition

Results Concerning Nickel Aluminisation with Application of Chemical Vapour Deposition Method Are Presented. Two-Step Processing under Investigation Consists of Al Chloride Formation in the Primary Vessel and Al Deposition in the Secondary One. the Initial Gas Stream Is Composed of Hcl Dissolved in H2at Various Ratios. it Was Shown that the Choice of the [HCl]/[H2] Ratio and the Determination of the Optimum Temperature to Produce Most Preferential β-Nial Phase May Be Done with the Use of Thermodynamic Calculations. the Results Obtained with Application of Factsage Program Confirm Essential Influence of both Initial [HCl]/[H2] Ratio (in the Range between 0,05 and 100) and the Temperature in the Second Vessel (1123 K – 1323 K) on Aluminium Chloride Partial Pressures and Hence Aluminium Content in its Gaseous Donors and at the Substrate Surface (boundary Condition for Interdiffusion in Ni-Al System). it Was Confirmed that β-Nial Growth Is Favoured at Low [HCl]/[H2] Ratios and High Temperatures for which Alcl and AlCl2Partial Pressures Increase with Respect to that of AlCl3. the Thermodynamic Predictions Remain in Agreement with CVD Experiments. the Presented Thermodynamic Data May Be Used as a Source of Essential Information for Designing Further Experiments in this Field as Well as for Modelling of Solid-State Diffusion in Ni-Al System.

Neutron Detectors Made From Chemically Vapour Deposited Semiconductors

1997 ◽  
Vol 487 ◽  
Author(s):  
F. Foulon ◽  
P. Bergonzo ◽  
A. Brambilla ◽  
C. Jany ◽  
B. Guizard ◽  
...  
Keyword(s):  
Detection Efficiency ◽  
Low Cost ◽  
Chemical Vapour ◽  
Polycrystalline Diamond ◽  
Neutron Detection ◽  
Large Area ◽  
Neutron Detectors ◽  
Gadolinium Isotope ◽  
Neutron Detection Efficiency ◽  
Hydrogenated Amorphous

AbstractIn this paper, we present the results of investigations on the use of semiconductors deposited by chemical vapour deposition (CVD) for the fabrication of neutron detectors. For this purpose, 20 μm thick hydrogenated amorphous silicon (a-Si:H) pin diodes and 100 μm thick polycrystalline diamond resistive detectors were fabricated. The detectors were coupled to a neutron-charged particle converter : a layer of either gadolinium or boron (isotope 10 enriched) deposited by evaporation. We have demonstrated the capability of such neutron detectors to operate at neutron fluxes ranging from 101 to 106 neutrons/cm2.s. The fabrication of large area detectors for neutron counting or cartography through the use of multichannel reading circuits is discussed. The advantages of these detectors include the ability to produce large area detectors at low cost, radiation hardness (∼ 4 Mrad for a-Si:H and ∼ 100 Mrad for diamond), and for diamond, operation at temperatures up to 500°C. These properties enable the use of these devices for neutron detection in harsh environments. Thermal neutron detection efficiency up to 22 % and 3 % are expected by coupling a-Si:H diodes and diamond detectors to 3 μm thick gadolinium (isotope 157) and 2 μm thick boron layers, respectively.

A New Approach Using Artificial Substrates for Growth of High-Quality Precipitate-Free HTS Thin Films, Toward Electronic Device Applications

2005 ◽  
Vol 868 ◽  
Author(s):  
K. Endo ◽  
P. Badica ◽  
H. Sato ◽  
H. Akoh
Keyword(s):  
Thin Films ◽  
Electronic Device ◽  
Growth Conditions ◽  
Device Fabrication ◽  
Artificial Substrates ◽  
High Quality ◽  
New Approach ◽  
Mesa Structure ◽  
Device Applications ◽  
And Performance

AbstractHigh quality thin films of HTS have been grown by MOCVD on substrates with artificial steps of predefined height and width. The surface of the films grown on the steps having width equal to the ‘double of the migration length' of the atomic species depositing on the substrate is totally free of precipitates: precipitates are gathered at the step edges where the free energy is lowest. The method has several advantages: it is simple, universal (it is independent of the materials, substrates, deposition technique or application) and allows control of precipitates segregates so that the quality and growth conditions of the films are the same as for the films grown on conventional substrates. The method is expected to result in new opportunities for the device fabrication, design and performance. As an example we present successful fabrication of a mesa structure showing intrinsic Josephson effect. We have used thin films of Bi-2212/Bi-2223 superstructure grown on (001) SrTiO3 single crystal substrates with artificial steps of 20 μm.

Detailed surface analysis of V-defects in GaN films on patterned silicon(111) substrates by metal–organic chemical vapour deposition

2019 ◽  
Vol 52 (3) ◽  
pp. 637-642 ◽  
Author(s):  
Jiang-Dong Gao ◽  
Jian-Li Zhang ◽  
Xin Zhu ◽  
Xiao-Ming Wu ◽  
Chun-Lan Mo ◽  
...  
Keyword(s):  
Growth Rate ◽  
Chemical Vapour ◽  
Direct Consequence ◽  
Growth Conditions ◽  
Organic Chemical ◽  
Film Boundary ◽  
Detailed Surface ◽  
Boundary Facet ◽  
Metal Organic ◽  
Gan Film

The growth mechanism of V-defects in GaN films was investigated. It was observed that the crystal faces of both the sidewall of a V-defect and the sidewall of the GaN film boundary belong to the same plane family of \{ {{{10\bar 11}}} \}, which suggests that the formation of the V-defect is a direct consequence of spontaneous growth like that of the boundary facet. However, the growth rate of the V-defect sidewall is much faster than that of the boundary facet when the V-defect is filling up, implying that lateral growth of \{ {{{10\bar 11}}} \} planes is not the direct cause of the change in size of V-defects. Since V-defects originate from dislocations, an idea was proposed to correlate the growth of V-defects with the presence of dislocations. Specifically, the change in size of the V-defect is determined by the growth rate around dislocations and the growth rate around dislocations is determined by the growth conditions.

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