The Formation and Behavior of Particles in Silane Discharges

1999 ◽  
Vol 557 ◽  
Author(s):  
Alan Gallagher
Keyword(s):  
Growth Rate ◽  
Film Growth ◽  
Particle Density ◽  
Plasma Chemistry ◽  
Particle Growth ◽  
Rf Plasma ◽  
Electrode Gap ◽  
Plasma Parameters ◽  
Rf Discharges ◽  
And Behavior

AbstractParticle growth in silane RF discharges, and the incorporation of particles into hydrogenated-amorphous-silicon (a-Si:H) devices is described. These particles have a structure similar to a-Si:H, but their incorporation into the device is believed to yield harmful voids and interfaces. Measurements of particle density and growth in a silane RF plasma, for particle diameters of 8-50 nm, are described. This particle growth rate is very rapid, and decreases in density during the growth indicate a major flux of these size particles to the substrate. Particle densities are a very strong function of pressure, film growth rate and electrode gap, increasing orders of magnitude for small increases in each parameter. A full plasma- chemistry model for particle growth from SiHm radicals and ions has been developed, and is outlined. It yields particle densities and growth rates, as a function of plasma parameters, which are in qualitative agreement with the data. It also indicates that, in addition to the diameter >2 nm particles that have been observed in films, a very large flux of SixH,, molecular radicals with × >1 also incorporate into the film. It appears that these large radicals yield more than 1% of the film for typical device-deposition conditions, so this may have a serious effect on device properties.

Comparative Study on in-situ Ellipsometric Monitoring of III-Nitride Film Growth via Plasma-Enhanced Atomic Layer Deposition

2019 ◽  
Vol 28 (03n04) ◽  
pp. 1940020
Author(s):  
Adnan Mohammad ◽  
Deepa Shukla ◽  
Saidjafarzoda Ilhom ◽  
Brian Willis ◽  
Ali Kemal Okyay ◽  
...  
Keyword(s):  
Growth Rate ◽  
Real Time ◽  
Film Growth ◽  
Atomic Layer ◽  
Layer Growth ◽  
In Situ Monitoring ◽  
Rf Plasma ◽  
Nitride Film ◽  
The Impact

In this paper a comparative in-situ ellipsometric analysis is carried out on plasma-assisted ALD-grown III-nitride (AlN, GaN, and InN) films. The precursors used are TMA, TMG, and TMI for AlN, GaN, and InN respectively, while Ar is used as purge gas. For all of the films N2/H2/Ar plasma was used as the co-reactant. The work includes real-time in-situ monitored saturation curves, unit ALD cycle analysis, and >500 cycle film growth runs. In addition, the films are grown at different substrate temperatures to observe the impact of temperature not only on the growth rate but on how it influenced the precursor chemisorption, ligand removal, and nitrogen incorporation surface reactions. All three nitride films confirm fairly linear growth character. The growth rate per cycle (GPC) for each film is also measured with respect to rf-plasma power to obtain the surface saturation conditions during ALD growth. The real-time in-situ monitoring of the film growth can really be beneficial to understand the atomic layer growth and film formation in each individual ALD cycle.

Pecvd RF Discharge Models Review

1989 ◽  
Vol 165 ◽  
Author(s):  
Alan Garscadden
Keyword(s):  
Kinetic Models ◽  
Plasma Chemistry ◽  
Plasma Electron ◽  
Secondary Emission ◽  
Rf Discharge ◽  
Data Sets ◽  
Plasma Parameters ◽  
Rf Discharges ◽  
Ion Collisions ◽  
Boundary Interaction

AbstractThis paper presents a concise and subjective summary of the rapid progress that has been made in the understanding of the essential features of RF discharges. The paper concentrates on introducing the important concepts used in modeling the rf discharge. The discharges have been modeled from several distinctly different approaches. These include circuit, beamdiffusion, plasma fluid or continuum, and particle kinetic models. The treatments have their usefulness depending on the application. The circuit models give easily parameterized results, power deposition, and phase angles between voltage and current, however, they do not describe the important plasma chemistry and the source terms for deposition and etching. The newer continuum models efficiently give self-consistent plasma parameters for higher pressure discharges but synergistic ion and neutral interactions with surfaces are difficult to include. The particle kinetic models can include many effects without approximations, however they need extensive data sets and long computer run times. The coupling of improved diagnostics and the different theories has resulted in a convergence of their conclusions. There are four distinct energy-gain mechanisms in the RF discharge : a bulk plasma excitation; electron beam excitation resulting from secondary emission from ion collisions with the electrodes; wave-riding acceleration on the sheath oscillation (collisional: Kushner); and a noncollisional plasma electron-sheath boundary interaction (Godyak). The relative contributions are sensitive functions of the gas mixture, pressure, frequency and RF voltage.

Better control over the onset of microcrystallinity in fast-growing silicon network

2004 ◽  
Vol 19 (9) ◽  
pp. 2597-2603 ◽  
Author(s):  
Sumita Mukhopadhyay ◽  
Debajyoti Das ◽  
Swati Ray
Keyword(s):  
Growth Rate ◽  
High Pressure ◽  
Deposition Rate ◽  
Film Growth ◽  
Electrical Power ◽  
Rf Plasma ◽  
High Deposition Rate ◽  
Deposition Parameter ◽  
Fast Growing ◽  
Film Growth Rate

In view of obtaining a Si:H network at the onset of microcrystallinity at a high deposition rate, we have adopted an intelligent approach to find out a tricky plasma condition in radio frequency (rf) plasma-enhanced chemical vapordeposition that provides a better control on growth introducing retarded microcrystallization. The deposition parameter includes a combination of high electrical power applied to the (SiH4+H2)-plasma and high gas pressure in thereaction chamber. High rf power increases the number density of film-forming precursors as well as atomic H density in the plasma, which helps to increase thefilm deposition rate and to promote microcrystallinity, respectively. In addition,high pressure helps not only to increase the film-growth rate by producing a dense plasma but also retards the microcrystallization process by increasing significantlythe gas phase collision frequency and consequently reducing the effective reactivityof atomic H on the surface of a fast-growing Si:H network. A combination of high-power and high-pressure plasma conditions provides a reasonably wide rangeof H2 dilution to work with and better control in producing a Si:H network at theonset of microcrystallinity, while increasing the film-growth rate.

Particle Production in High Density Silane Plasma

2002 ◽  
Vol 737 ◽  
Author(s):  
Z. Shen ◽  
T. Kim ◽  
U. Kortshagen ◽  
P. H. McMurry ◽  
S. A. Campbell
Keyword(s):  
Electron Microscopy ◽  
Growth Rate ◽  
Particle Production ◽  
Particle Density ◽  
Particle Growth ◽  
Monodisperse Particles ◽  
Particle Generation ◽  
Potential Applications ◽  
Silane Plasma ◽  
Silicon Particles

ABSTRACTTo understand the mechanisms of nanoparticle formation and its potential applications, we have investigated silicon particles formed in various gasses in an inductive coupled plasma (ICP) system and have measured their structural properties by electron microscopy. Particle generation in pure SiH4 and SiH4/H2 are reported. ICP silane plasmas are shown to be an interesting and versatile source of nanoparticles. Three regimes are mapped out: a regime of no observable particle growth at the lowest pressures, a regime of polydisperse and agglomerated particles at the highest pressures, and a regime yielding highly monodisperse particles at intermediate pressures. Conditions that generate these nonagglomerated, extremely monodisperse silicon particles are emphasized. For H2 dilutions less than 92%, the growth rate is almost independent of H2 partial pressure. Particle growth decreases steadily when the H2 dilution is increased further. TEM images, however, indicate that the addition of hydrogen decreases the particle density. At higher dilution ratios, polycrystalline particles are obtained. Under all other conditions the particles are amorphous. Reasons for this behavior are explored.

scholarly journals Properties and Mechanism of PEALD-In2O3 Thin Films Prepared by Different Precursor Reaction Energy

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 978
Author(s):  
Ming-Jie Zhao ◽  
Zhi-Xuan Zhang ◽  
Chia-Hsun Hsu ◽  
Xiao-Ying Zhang ◽  
Wan-Yu Wu ◽  
...  
Keyword(s):  
Growth Rate ◽  
Substrate Temperature ◽  
Film Growth ◽  
Atomic Layer ◽  
Amorphous Structure ◽  
Reaction Energy ◽  
Film Growth Rate ◽  
In2o3 Film ◽  
Intermediate Temperature Range ◽  
Layer Deposition

Indium oxide (In2O3) film has excellent optical and electrical properties, which makes it useful for a multitude of applications. The preparation of In2O3 film via atomic layer deposition (ALD) method remains an issue as most of the available In-precursors are inactive and thermally unstable. In this work, In2O3 film was prepared by ALD using a remote O2 plasma as oxidant, which provides highly reactive oxygen radicals, and hence significantly enhancing the film growth. The substrate temperature that determines the adsorption state on the substrate and reaction energy of the precursor was investigated. At low substrate temperature (100–150 °C), the ratio of chemically adsorbed precursors is low, leading to a low growth rate and amorphous structure of the films. An amorphous-to-crystalline transition was observed at 150–200 °C. An ALD window with self-limiting reaction and a reasonable film growth rate was observed in the intermediate temperature range of 225–275 °C. At high substrate temperature (300–350 °C), the film growth rate further increases due to the decomposition of the precursors. The resulting film exhibits a rough surface which consists of coarse grains and obvious grain boundaries. The growth mode and properties of the In2O3 films prepared by plasma-enhanced ALD can be efficiently tuned by varying the substrate temperature.

scholarly journals Effects of magnetic perturbations and radiation on the runaway avalanche

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
P. Svensson ◽  
O. Embreus ◽  
S. L. Newton ◽  
K. Särkimäki ◽  
O. Vallhagen ◽  
...  
Keyword(s):  
Growth Rate ◽  
Runaway Electrons ◽  
Plasma Parameters ◽  
Perturbative Approach ◽  
Efficient Simulation ◽  
Strong Current ◽  
Magnetic Perturbations ◽  
Space Dynamics ◽  
Stochastic Magnetic Fields ◽  
Mitigation Methods

The electron runaway phenomenon in plasmas depends sensitively on the momentum- space dynamics. However, efficient simulation of the global evolution of systems involving runaway electrons typically requires a reduced fluid description. This is needed, for example, in the design of essential runaway mitigation methods for tokamaks. In this paper, we present a method to include the effect of momentum-dependent spatial transport in the runaway avalanche growth rate. We quantify the reduction of the growth rate in the presence of electron diffusion in stochastic magnetic fields and show that the spatial transport can raise the effective critical electric field. Using a perturbative approach, we derive a set of equations that allows treatment of the effect of spatial transport on runaway dynamics in the presence of radial variation in plasma parameters. This is then used to demonstrate the effect of spatial transport in current quench simulations for ITER-like plasmas with massive material injection. We find that in scenarios with sufficiently slow current quench, owing to moderate impurity and deuterium injection, the presence of magnetic perturbations reduces the final runaway current considerably. Perturbations localised at the edge are not effective in suppressing the runaways, unless the runaway generation is off-axis, in which case they may lead to formation of strong current sheets at the interface of the confined and perturbed regions.

scholarly journals Effect of Voltage Pulse Width and Synchronized Substrate Bias in High-Power Impulse Magnetron Sputtering of Zirconium Films

Coatings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 7
Author(s):  
Chin-Chiuan Kuo ◽  
Chun-Hui Lin ◽  
Jing-Tang Chang ◽  
Yu-Tse Lin
Keyword(s):  
Growth Rate ◽  
Magnetron Sputtering ◽  
High Power ◽  
Pulse Width ◽  
Film Growth ◽  
Highly Charged Ions ◽  
Argon Pressure ◽  
Hexagonal Prism ◽  
Film Growth Rate ◽  
Charged Ions

The Zr film microstructure is highly influenced by the energy of the plasma species during the deposition process. The influences of the discharge pulse width, which is the key factor affecting ionization of sputtered species in the high-power impulse magnetron sputtering (HiPIMS) process, on the obtained microstructure of films is investigated in this research. The films deposited at different argon pressure and substrate biasing are compared. With keeping the same average HiPIMS power and duty cycle, the film growth rate of the Zr film decreases with increasing argon pressure and enhancing substrate biasing. In addition, the film growth rate decreases with the elongating HiPIMS pulse width. For the deposition at 1.2 Pa argon, extending the pulse width not only intensifies the ion flux toward the substrate but also increases the fraction of highly charged ions, which alter the microstructure of films from individual hexagonal prism columns into a tightly connected irregular column. Increasing film density leads to higher hardness. Sufficient synchronized negative substrate biasing and longer pulse width, which supports higher mobility of adatoms, causes the preferred orientation of hexagonal α-phase Zr films from (0 0 0 2) to (1 0 1¯ 1). Unlike the deposition at 1.2 Pa, highly charged ions are also found during the short HiPIMS pulse width at 0.8 Pa argon.

Direct Nucleation of Crystalline SiGe on Substrates by Reactive Thermal CVD with Si2H6 and GeF4

1997 ◽  
Vol 467 ◽  
Author(s):  
Fumio Yoshizawa ◽  
Kunihiro Shiota ◽  
Daisuke Inoue ◽  
Jun-ichi Hanna
Keyword(s):  
Growth Rate ◽  
Gas Phase ◽  
Heterogeneous Nucleation ◽  
Homogeneous Nucleation ◽  
Film Growth ◽  
Early Stage ◽  
Gaseous Mixture ◽  
The Other ◽  
Thermal Cvd ◽  
Initial Deposition

ABSTRACTPolycrystalline SiGe (poly-SiGe) film growth by reactive thermal CVD with a gaseous mixture of Si2H6 and GeF4 was investigated on various substrates such as Al,Cr, Pt, Si, ITO, ZnO and thermally grown SiO2.In Ge-rich film growth, SEM observation in the early stage of the film growth revealed that direct nucleation of crystallites took place on the substrates. The nucleation was governed by two different mechanisms: one was a heterogeneous nucleation on the surface and the other was a homogeneous nucleation in the gas phase. In the former case, the selective nucleation was observed at temperatures lower than 400°C on metal substrates and Si, where the activation of adsorbed GeF4 on the surface played a major role for the nuclei formation, leading to the selective film growth.On the other hand, the direct nucleation did not always take place in Si-rich film growth irrespective of the substrates and depended on the growth rate. In a growth rate of 3.6nm/min, the high crystallinity of poly-Si0.95Ge0.05in a 220nm-thick film was achieved at 450°C due to the no initial deposition of amorphous tissue on SiO2 substrates.

scholarly journals The Mixed-Electrode Concept for Understanding Growth and Aggregation Behavior of Metal Nanoparticles in Colloidal Solution

2018 ◽  
Vol 8 (8) ◽  
pp. 1343
Author(s):  
Johann Köhler ◽  
Andrea Knauer
Keyword(s):  
Metal Nanoparticles ◽  
Colloidal Solution ◽  
Particle Growth ◽  
Open Circuit ◽  
Aggregation Behavior ◽  
Nanoparticle Growth ◽  
Aspect Ratios ◽  
Spherical Metal Nanoparticles ◽  
High Yields ◽  
And Behavior

The growth and aggregation behavior of metal nanoparticles can be modulated by surfactants and different other additives. Here the concept of how open-circuit mixed electrodes helps to understand the electrical aspects of nanoparticle growth and the consequences for the particle geometries is discussed. A key issue is the self-polarization effect of non-spherical metal nanoparticles, which causes a local decoupling of anodic and partial processes and asymmetry in the local rates of metal deposition. These asymmetries can contribute to deciding to the growth of particles with high aspect ratios. The interpretation of electrochemical reasons for particle growth and behavior is supported by experimental results of nanoparticle syntheses supported by microfluidics which can supply high yields of non-spherical nanoparticles and colloidal product solutions of high homogeneity.

Stress Evaluation on Hetero-Epitaxial 3C-SiC Film on (100) Si Substrates

2012 ◽  
Vol 717-720 ◽  
pp. 521-524 ◽  
Author(s):  
Ruggero Anzalone ◽  
M. Camarda ◽  
C. Locke ◽  
J. Carballo ◽  
N. Piluso ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth Process ◽  
Film Growth ◽  
Raman Shift ◽  
Fundamental Parameter ◽  
Free Standing ◽  
Si Substrates ◽  
Shift Analysis ◽  
Hydrogen Carrier ◽  
The Impact

SiC is a candidate material for micro- and nano-electromechanical systems (MEMS and NEMS). In order to understand the impact that the growth rate has on the residual stress of CVD-grown 3C-SiC hetero-epitaxial films on Si substrates, growth experiments were performed and the resulting stress was evaluated. Film growth was performed using a two-step growth process with propane and silane as the C and Si precursors in hydrogen carrier gas. The film thickness was held constant at ~2.5 µm independent of the growth rate so as to allow for direct films comparison as a function of the growth rate. Supported by profilometry, Raman and micro-machined free-standing structures, this study shows that the growth rate is a fundamental parameter for low-defect and low-stress hetero-epitaxial growth process of 3C-SiC on Si substrates. Stress analysis performed by modify Stoney’s equation trough optical curvature measurement, Raman shift analysis and micro-machining of free-standing structures that shows apparent disagreement about the nature of the stress. These odds between the experimental data can be explained assuming a strong stress field located in the substrate and related to defects generated in the silicon during the growth process.

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