Dissertations / Theses: 'Radio frequency inductively-coupled plasma'

1

Chen, Bing-Hung. "Inductively coupled radio-frequency discharges." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244566.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Canturk, Mehmet. "Modeling Of Helically Applied Current To The Inductively Coupled Radio Frequency Plasma Torch In Two Dimensions." Phd thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/3/12604691/index.pdf.

Full text

Abstract:

The electrodeless plasma discharge is typically driven by radio frequency (RF) power supply within the range (0.2 ¡
40 MHz). The applied power is coupled into the plasma inductively called inductively coupled plasma (ICP). RF ICP technique has achieved significance importance in a diversity of research and industrial applications for over the last threes decades. It is still required to undertake both theoretical and experimental research. In this work, RF ICP technique is applied on the torch modeling in 2D. Based on extended electromagnetic vector potential representation, an axisymmetric model in 2D is proposed for the calculations of the electromagnetic fields in an RF ICP torch. The influence of axial vector potential is included to the vector potential formulations. This is achieved by imposing a helical current carrying wire configuration. The corresponding governing equations are solved numerically by applying finite element method (FEM) using commercial partial differential equation solver (Flex PDE3). Based on this model, the plasma behavior and properties are examined in terms of plasma parameters. Besides, a comparative iii analysis is made between proposed model called helical configuration and the one currently available in the literature called circular configuration. This study shows relatively little difference between temperature fields predicted by two models. However, significant difference is observed between corresponding flows and electromagnetic fields. Especially, tangential flow which is observed in helical configuration vanishes in circular configuration. The proposed model offers an effective means of accounting for the variations of the helical coil geometry on the flow and temperature fields and achieving a better representation of the electromagnetic fields in the discharge. Finally, it is concluded that minimum number of turns (n = 2) yields significant difference between two models whereas, maximum allowable number of turns yield no distinctions on the results of two models in terms of azimuthally applied current. However, axial effect of current still exists but very small with respect to the result obtained with minimum number of turns.

APA, Harvard, Vancouver, ISO, and other styles

3

Yang, Suidong. "Diagnostics and modelling of an inductively coupled RF low-pressure low-temperature plasma." Thesis, n.p, 1998. http://oro.open.ac.uk/19841/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Rainey, Joe Seaburn. "Synthesis of fullerenes and metallic fullerenes by the utilization of an argon radio frequency inductively coupled plasma." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/27679.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Wegner, Thomas [Verfasser]. "Comprehensive study of the discharge mode transition in inductively coupled radio frequency plasmas / Thomas Wegner." Greifswald : Universitätsbibliothek Greifswald, 2016. http://d-nb.info/1122581629/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Miller, Charles William. "Surface characterization of inductively coupled radio frequency plasma treated glassy carbons by x-ray photoelectron spectroscopy and scanning electron microscopy /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487266362335601.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Miller, Joseph. "Direct Multielemental Analysis of Solid Samples Using Laser Ablation Inductively Coupled Plasma Mass Spectometry and Pulsed Radio Frequency Glow Discharge Mass Spectrometry." TopSCHOLAR®, 2003. http://digitalcommons.wku.edu/theses/556.

Full text

Abstract:

Direct solid sampling is an area of analytical research that has generated a large amount of interest in recent years. Two analysis systems offering fast and nondestructive methods of determining the elemental composition of substances, without requiring complicated sample preparation procedures, are laser ablation inductively coupled plasma mass spectroscopy (LA-ICPMS) and radio frequency glow discharge mass spectroscopy (rf-GDMS). A Cetac LSX-200 laser system coupled to a LECO Renaissance ICPMS was utilized to analyze coal and ash samples prepared by incorporation into a lithium borate matrix to form a disk. In addition, a VG 9000 Glow Discharge Mass Spectrometer (GDMS) with Nier-Johnson reverse ion optic geometry, equipped with a radio frequency source (rf-source), was used for the determination of nonconductors or insulators in addition to the normal metals and semiconductors previously determined by dc-source analysis. Further addition of a pulse generator to the rf-source resulted in a variable duty cycle, allowing greater ionization efficiency without the risk of catastrophic damage to the sample. The results of this research indicate that the LA-ICPMS system can be used to directly determine the composition of ash samples, with further method development, and that the Prf-GDMS system can be used successfully to analyze nonconductive solid samples including bone tissue.

APA, Harvard, Vancouver, ISO, and other styles

8

Dukovský, Daniel. "Depozice bioaktivních keramických vrstev pomocí technologie RF-ICP." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-442600.

Full text

Abstract:

Tato diplomová práce se zabývá problematikou plazmového nanášení bioaktivních keramických povlaků hydroxylapatitu s využitím technologie radio-frekvenčně buzeného indukčně vázaného plazmatu. Cílem bylo optimalizovat proces a nanést kompaktní hydroxylapatitové povlaky na substráty z titanové slitiny Ti6Al4V. Nanesené vzorky byly následně podrobeny analýzám povrchové drsnosti, mikrostruktury a fázového složení. Ze získaných výsledků byly vyvozeny závěry, které byly srovnány s dalšími odbornými pracemi zabývajícími se příbuznou problematikou.

APA, Harvard, Vancouver, ISO, and other styles

9

Liang, Dong Cuan. "Development and characterization of atmospheric pressure radio frequency capacitively coupled plasmas for analytical spectroscopy." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/30590.

Full text

Abstract:

An atmospheric pressure radio frequency capacitively coupled plasma (CCP) has been developed and characterized for applications in atomic emission spectrometry (AES), atomic absorption spectrometry (AAS) and gas chromatography (GC). The CCP torch was initially designed as an atom reservoir for carrying out elemental analysis using atomic absorption. Functionally, the device consists of two parts, the CCP discharge tube and the tantalum strip electrothermal vaporization sample introduction system. The torch design provides for very effective energy transfer from the power supply to the plasma by capacitive coupling. Therefore, the plasma can be generated at atmospheric pressure with a flexible geometry. The plasma can be operated at very low rf input powers (30-600 W) enabling optimal conditions for atom resonance line absorption measurements. Absorption by the analyte takes place within the plasma discharge which is characterized by a long path length (20 cm) and low support gas flow rate (0.2 L/Min). Both of these characteristics ensure a relatively long residence time. The device exhibits linear calibration plots and provides sensitivities in the range of 3.5-40 pg. A preliminary measurement gave a Fe I excitation temperature of approximately 4000 K for the discharge. At this temperature, potential chemical interferences are likely to be minimal. Chemical interferences for Fe, Al, As, Ca, Co, Cd, Li, Mo and Sr were negligible in the determination of silver. Chloride interference, which is prevalent in GF-AAS, was not found. The amount of Ag found in a SMR#1643b (NIST) water sample was 9.5 ± 0.5 ng/g which fell in the certified range of 9.8 ± 0.8 ng/g. Spikes of 30 ng/g and 60 ng/g of silver were added to the SRM and recoveries were found to be in a range from 105 % to 96.2 %. The RSD obtained for 7 replicates of 270 pg silver was 4.6 %. The results for the CCP AES are even more promising. The interferences of thirteen elements are negligible in the determination of silver. The chloride interference was not found. The detection limits for Ag, Cd, Li, Sb and B are 0.7, 0.7, 2, 80 and 400 pg respectively. The amount of silver found in a SRM#1643b (NIST) water sample was 9.3 ± 0.5 ng/g which also fell in the certified range of 9.8 ±0.8 ng/g. Spikes of 30 ng/g and 60 ng/g of silver were added into the SRM#1643b (NIST) samples; the recoveries were found to range from 97 % to 104 %. The RSD obtained for 7 analyses of 270 pg silver were 1.5 % for CCP-AES. It was also found that the signal to noise ratios (S/N) are higher in the AES mode than those in the AAS mode in the same CCP atomizer. In order to exploit advantages inherent in both GF-AAS and I CP-AES, an atmospheric pressure capacitively coupled plasma sustained inside a graphite furnace was developed. This source combines the high efficiency of atomization in furnaces and the high efficiency of the excitation in atmospheric pressure plasmas. In general, plasma sources are able to effectively excite high-lying excited states for most metals and non-metals and can also ionize vaporized elements. Therefore the possibility exists of using non-resonance lines to avoid the effects of self-absorption at high analyte concentrations. Ion lines may also be used in cases where they provide better sensitivity or freedom from spectral interferences. This source also offers the ability to independently optimize vaporization and excitation. However, the most important aspect of this new source is that it can be used for simultaneous, multielement determinations of small sized samples in a graphite furnace atomizer, a design which has been proven to be effective over many years of use. Preliminary quantitative characteristics of this new atmospheric pressure plasma emission source have been studied. The detection limit for Ag of 0.3 pg is lower than the value of 0.4 pg reported for GF-AAS. Variants of the CCP, including a gas chromatography (GC) detector, combinations of laser ablation - CCP, rf sputtering - CCP direct solid analysis, and its application as an intense spectral lamp have been developed and are reported in this dissertation.
Science, Faculty of
Chemistry, Department of
Graduate

APA, Harvard, Vancouver, ISO, and other styles

10

O'Neill, Colm Philip. "Numerical simulations of plasma dynamics and chemistry in dual radio-frequency and pulse driven capacitively coupled atmosphere pressure plasmas." Thesis, Queen's University Belfast, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.696157.

Full text

Abstract:

This thesis presents the results of numerical models used to investigate the influence of the operating conditions of a micro atmospheric pressure plasma jet, on the electron dynamics, ionisation/sustainment mechanisms and resultant plasma chemistry. The aim is to determine the, optimum operating conditions of this discharge for enhancing and controlling the underlying plasma processes and production/composition of useful reactive species. Both nonlinear frequency coupling and pulsed excitation have been shown to influence the underlying processes governing the electron dynamics in radio-frequency driven atmospheric pressure plasmas, here the effects of operating a micro atmospheric pressure 'plasma jet (μ-APPJ) using dual frequency (2F) and pulsed excitation are explored. Several multi-scale numerical models based on hydrodynamic equations with a semi-kinetic treatment of the electrons are used to investigate the influence of the operating mode on the plasma dynamics and chemistry. The models consider a helium background gas with a small molecular admixture of either Nitrogen or Oxygen, and range in complexity, with the most complex model accounting for 184 reactions amongst 20 species. Each model is found to agree well with experimental benchmarks. Using 2F excitation, it is found that variations of power density, voltage ratio and phase relationship provide separate control over the electron density, mean electron energy and electro-negativity. Using Pulsed excitation, variations of the pulse width and repetition rate are also found to directly influence the electron density, mean electron energy and electro-negativity. In both cases this is exploited to directly influence the phase dependent and time averaged effective EEPF, which enables tailoring of the EEPF for enhanced control over the plasma chemical kinetics. This is shown to allow control over the production and composition of useful reactive species, namely reactive oxygen species.

APA, Harvard, Vancouver, ISO, and other styles

11

Greb, Arthur. "Dynamics of the plasma-surface interface in capacitively coupled radio-frequency oxygen plasmas : coupling numerical simulations with optical diagnostics." Thesis, University of York, 2013. http://etheses.whiterose.ac.uk/4980/.

Full text

Abstract:

Plasma processing on industrial scale is becoming increasingly complex, demanding new strategies for process control and monitoring. Of particular interest is the energy transport in the interface region between the non-equilibrium low-pressure plasma and the surface. The individual plasma components have varying properties and exhibit different dynamics, which enable numerous chemical and physical modifications of surfaces simultaneously. Measurements of the in-situ surface condition and important chemically active radical species are extremely challenging. The most promising approach to overcome these challenges to achieve advanced process control is the active coupling of numerical simulations and experiments. In this regard, numerical simulations are a well-established technique to study fundamental plasma parameters and plasma dynamics for a variety of discharge sources. The utilised numerical simulation is an experimentally benchmarked 1D fluid model, with semi-kinetic treatment of electrons and an improved energy dependent ion mobility treatment. This model is applied for a geometrically symmetric and asymmetric capacitively coupled oxygen RF discharge. Within the investigated pressure range of 10 Pa - 100 Pa the simulations predict that changing surface conditions have a significant effect on dynamics of the plasma-surface interface. In particular, the surface loss probability and lifetime of metastable singlet delta oxygen as well as the secondary electron emission coefficient are identified to substantially influence the electronegativity and the plasma sheath dynamics on a nanosecond timescale. Phase resolved optical emission spectroscopy measurements, utilising different surface materials, confirm these predictions by comparing measured and simulated excitation features for three different optical emission lines. Through the synergistic coupling of numerical simulations and experiments, the surface work functions as well as other key surface parameters are assessed. Furthermore, the use of an advanced actinometry technique, demonstrated by coupling simple electron kinetic simulations and optical measurements, enables measurements of the spatial distribution of radical atomic oxygen densities and local electron energies over the total discharge volume.

APA, Harvard, Vancouver, ISO, and other styles

12

Blessington, Jon C. "Measurements of metastable atom density using energies and densities of energetic "fast" electrons detected in the electron energy distribution function associated with the afterglow plasma produced by a radio frequency inductively coupled plasma helium discharge." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5214.

Full text

Abstract:

Thesis (M.S.)--West Virginia University, 2007.
Title from document title page. Document formatted into pages; contains v, 36 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 21).

APA, Harvard, Vancouver, ISO, and other styles

13

Kadetov, Victor A. "Diagnostics and modeling of an inductively coupled radio frequency discharge in hydrogen." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972011854.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

O'Brien, Kathleen. "Inductively coupled radio frequency power transmission system for wireless systems and devices /." Aachen : Shaker, 2007. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=015959229&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

O'Brien, Kathleen [Verfasser]. "Inductively Coupled Radio Frequency Power Transmission System for Wireless Systems and Devices / Kathleen O'Brien." Aachen : Shaker, 2007. http://d-nb.info/1166516717/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Bandyopadhyay, Mainak. "Studies of an inductively coupled negative hydrogen ion radio frequency source through simulations and experiments." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972317309.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Zaka-ul-Islam, Mujahid. "A study of electron dynamics in a single and dual frequency inductively coupled plasma system." Thesis, Queen's University Belfast, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.580132.

Full text

Abstract:

The single and dual frequency ICPs are studied in this thesis, mostly in oxygen; a simple electronegative gas. The diagnostics used here include; PROES, laser photodetachment and, Hairpin and Langmuir probes. Many issues of the fundamental understanding were investigated which include; the influence of the electronegativity on the electron density, E-H mode transition, collisionless heating, RF biased ICPs and the pulsed ICPs. The changes in the electronegativity are found here to be related to the heating mechanisms in the plasma. ICPs are well known to operate in E or H mode, depending on the applied power. The PROES measurements showed that both capacitive and inductive power couplings are simultaneously present in stable E and H modes, close to the transition. The individual contribution of capacitive and inductive power is also estimated here, using some new techniques. In pulsed ICPs, E and H like modes with simultaneous contribution of the capacitive and inductive couplings are also observed. The PROES measurements in the H-mode of ICPs, operated in the collisionless pressure regime, shows axially two maxima structure in the discharge, possibly because of the negative power absorption in the middle of the ICPs. The spatio-temporal excitation measurements in a RF biased ICPs (or dual frequency ICPs) showed that the coupling of the bias with tile capacitive coupling of the coil play a . significant role in the electron heating. The power and pressure regime where RF bias significantly influences the electron density and heating, is identified. The measurements also indicate the limitations of the independent control of the ion flux and energy. The phase between the ICP and bias could be used to decrease or enhance the influence of bias on electron heating. The electron density measurements showed that the RF bias can improve the radial uniformity and edge to centre electron density ratio.

APA, Harvard, Vancouver, ISO, and other styles

18

Dobkevicius, Mantas. "Modelling and design of inductively coupled radio frequency gridded ion thrusters with an application to Ion Beam Shepherd type space missions." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/413768/.

Full text

Abstract:

Recently proposed space missions such as Darwin, LISA and NGGM have encouraged the development of electric propulsion thrusters capable of operating in the micro-Newton (N) thrust range. To meet these requirements, radio frequency (RF) gridded ion thrusters need to be scaled down to a few centimetres in size. Due to the small size of these thrusters, it is important to accurately determine the thermal and performance parameters. To achieve this, an RF ion thruster model has been developed, composed of plasma discharge, 2D axisymmetric ion extraction, 3D electromagnetic, 3D thermal and RF circuit models. The plasma discharge model itself is represented using 0D global, 2D axisymmetric and 3D molecular neutral gas, and Boltzmann electron transport sub-models. This is the rst time such a holistic/comprehensive model has been created. The model was successfully validated against experimental data from the RIT 3.5 thruster, developed for the NGGM mission. Afterwards, the computational model was used to design an RF gridded ion thruster for an Ion Beam Shepherd (IBS) type space debris removal mission. Normally, the IBS method requires two thrusters: one for impulse transfer (IT) and one for impulse compensation (IC). This thesis proposes a novel thruster concept for the IBS type missions where a single Double-Sided Thruster (DST) simultaneously producing ion beams for the IT and IC purposes is used. The advantage of DST design is that it requires approximately half the RF power compared with two single-ended thrusters and it has a much simpler sub-system architecture, lower cost, and lower total mass. Such a DST thruster was designed, built and tested, with the requirements and constraints taken from the LEOSWEEP space debris removal mission. During the experimental campaign, a successful extraction of two ion beams was achieved. The thesis has shown that it is possible to control the thrust magnitudes from the IT and IC sides by varying the number of apertures in each ion optics system, proving that the DST concept is a viable alternative for the LOESWEEP mission.

APA, Harvard, Vancouver, ISO, and other styles

19

Butt, Munam. "Systemization of RFID Tag Antenna Design Based on Optimization Techniques and Impedance Matching Charts." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23064.

Full text

Abstract:

The performance of commercial Radio Frequency Identification (RFID) tags is primarily limited by present techniques used for tag antenna design. Currently, industry techniques rely on identifying the RFID tag application (books, clothing, etc.) and then building antenna prototypes of different configurations in order to satisfy minimum read range requirements. However, these techniques inherently lack an electromagnetic basis and are unable to provide a low cost solution to the tag antenna design process. RFID tag performance characteristics (read-range, chip-antenna impedance matching, surrounding environment) can be very complex, and a thorough understanding of the RFID tag antenna design may be gained through an electromagnetic approach in order to reduce the tag antenna size and the overall cost of the RFID system. The research presented in this thesis addresses RFID tag antenna design process for passive RFID tags. With the growing number of applications (inventory, supply-chain, pharmaceuticals, etc), the proposed RFID antenna design process demonstrates procedures to design tag antennas for such applications. Electrical/geometrical properties of the antennas designed were investigated with the help of computer electromagnetic simulations in order to achieve optimal tag performance criteria such as read range, chip-impedance matching, antenna efficiency, etc. Experimental results were performed on the proposed antenna designs to compliment computer simulations and analytical modelling.

APA, Harvard, Vancouver, ISO, and other styles

20

Gao, Guangning. "Modelling and diagnostics of atmospheric argon radio frequency inductively coupled plasma." 2004. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=94738&T=F.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Shan, Yanguang. "A stochastic spray model for radio frequency inductively coupled plasmas." 2004. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=80305&T=F.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

"MODELING OF HELICALLY APPLIED CURRENT TO THE INDUCTIVELY COUPLED RADIO FREQUENCY PLASMA TORCH IN TWO DIMENSIONS." Phd thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/3/12604691/index.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Lin, Shi-Hao, and 林士豪. "Effects of different radio-frequency powers on inductively coupled plasma thermal chemical vapor deposition carbon thin films using ethene/nitrogen mixtures." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/32819060933429947588.

Full text

Abstract:

碩士
國立中興大學
材料科學與工程學系所
103
This study investigates the effects of different radio-frequency (rf) powers on the properties of carbon thin films prepared by thermal chemical vapor deposition (thermal CVD) enhanced with inductively coupled plasma. The residual gases in the thermal CVD process, thickness, microstructure, and electrical properties of carbon thin films are investigated by residual gases analyzer, field emission scanning electron microscopy, X-ray diffractometer, Raman scattering spectrometer, X-ray photoelectron spectrometer, and four-points probe. Residual gases analysis results reveal that the main species in the gas phase contain H2, CH3, CH4, C2H, C2H2, HCN, and N2 (or C2H4), in which H2 decreases with increasing the rf power, but HCN increases with increasing the rf power. Experimental results indicate that the deposition rate of carbon thin films decreases with increasing the rf power; this is because the increase of HCN suppresses the deposition of carbon films. The crystallinity and the ordering degree of carbon thin films increase with increasing the rf power. This is because the decrease of the deposition rate enhances the rearrangement of carbon atoms, which results in the increase of average grain size of carbon films. The number of sp2 carbon sites decreases with increasing the rf power; this is because the increase of the hydrogen content suppresses the formation of the sp2C=C bonds. Finally, the electrical resistivity of carbon thin films increases with increasing the rf power, this is resulted from the decrease of the number of the sp2 C=C bonding.

APA, Harvard, Vancouver, ISO, and other styles

24

Lai, Ti-Chuan, and 賴&;#24312;全. "Effects of different radio-frequency powers on the properties of carbon films by thermal chemical vapor deposition with inductively coupled plasma." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/67261956289012916889.

Full text

Abstract:

碩士
國立中興大學
材料科學與工程學系所
98
This study investigates the effects of different radio frequency (rf) powers on the properties of carbon films prepared by thermal chemical vapor deposition enhanced with inductively coupled plasma. The film thickness, microstructure, surface morphology, and electrical property of carbon films were investigated by field emission scanning electron microscopy, X-ray diffraction spectrometer, Raman scattering spectrometer, atomic force microscopy, contact angle meter, and four-points probe. The results indicate that the deposition rate increases as the rf power increases. Because the peak intensity of the substrate is much stronger than that of the graphite, the mean crystallite size（LC）has no trend with respect to the rf power. The in-plane crystallite size（La）decreases as the rf power increases. The ID/IG value increases as the rf-power increases, so the structure of carbon films becomes more disorder. The surface roughness of carbon films first decreases with increasing the rf power, but then increases as the rf power is over 250 W. The contact angle of carbon films increases with increasing the rf power in the beginning, but then decreases as the rf power is over 300 W. The electrical resistivity of the carbon films first decreases with increasing the rf power, but then increases as the rf power is over 300 W.

APA, Harvard, Vancouver, ISO, and other styles

25

Lai, Liang-Hsun, and 賴良訓. "Hermetically carbon-coated optical fibers prepared by thermal chemical vapor deposition enhanced with inductively coupled plasma of different radio-frequency powers." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/55956265831234840527.

Full text

Abstract:

碩士
國立中興大學
材料科學與工程學系所
98
This study investigates the effects of different radio-frequency (rf) powers on the properties of carbon coatings on optical fibers that are prepared by thermal chemical vapor deposition enhanced with inductively coupled plasma. Methane (16 sccm) and nitrogen (4 sccm) were used as the precursor gases, and rf powers were set between 0 and 400 W. The deposition temperature, working pressure, and deposition time were set to 975 ℃, 4 kPa, and 2 hours, respectively. The coating thickness, microstructure, surface roughness, surface property, electrical property, and low-temperature morphology of carbon coatings were investigated by field emission scanning electron microscopy, X-ray diffraction spectrometer, Raman scattering spectrometer, X-ray photoelectron spectrometer, atomic force microscopy, contact angle meter, four-points probe, and optical microscopy. The results indicate that the deposition rate increases as the rf power increases from 0 to 200 W, but the deposition rate decreases as the rf power exceeds 200 W. The mean crystallite size (Lc) increases with increasing the coating thickness, but the degree of ordering and in-plane crystallite size (La) decrease. Moreover, when the rf power increases, the carbon coatings have more sp2 carbon atoms and become graphite-like. The results also show that the surface roughness is inversely related to the water contact angle. As the rf power increases from 0 to 400 W, the electrical resistivity of carbon coatings decreases from 56.96 to 14.01 Ω‧μm. Finally, based on the low-temperature morphologies of carbon coatings, as the coating thickness exceeds 76 nm, the carbon coating has the ability to withstand thermal stress, and is good for use as a hermetical optical fiber coating.

APA, Harvard, Vancouver, ISO, and other styles

26

Kang, Hui-Hsiang, and 康惠翔. "Effects of radio-frequency power on the properties of carbon thin films prepared by thermal chemical vapor deposition enhanced with remote inductively coupled plasma using ethylene/ammonia mixtures." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/yc44h5.

Full text

Abstract:

碩士
國立中興大學
材料科學與工程學系所
103
This study investigates the effects of different radio-frequency (rf) powers on the properties of carbon thin films that are prepared by thermal chemical vapor deposition enhanced with inductively coupled plasma (ICP). Ethylene (16 sccm) and Ammonia (4 sccm) were used as the precursor gases, and rf powers were set as 0W、100W、200W、300W and 400 W. The deposition temperature, working pressure, and deposition time were set to 1248 K, 4 kPa, and 2 hours. Alternatively, the residual gases, coating thickness, microstructure, surface roughness, surface property, and electrical property of carbon coatings were investigated by Residual gases analyzer, Field emission scanning electron microscopy, X-ray diffraction spectrometer, Raman scattering spectrometer, X-ray photoelectron spectrometer, Atomic force microscopy, Contact angle meter, and Four-points probe, respectively. The results indicate that if the rf power increases from 0 to 400 W, the deposition rate decreases. This is because the H2 molecules or the carbon deposited in the ICP zone increases with the rf powers. The mean crystallite size (Lc) and in-plane crystallite size (La) increase with decreasing the coating thickness, and thus, the degree of ordering increases. Moreover, when the rf-power increases, sp2 carbon atoms easily become sp3 carbon atoms, so the content of sp2 atoms in the carbon coatings decreases. Besides, the results also show that when the rf- power increases, the water contact angle (water-proofing) decreases that is resulted from the decrease of sp2 carbon atoms; the surface roughness decreases from 0 to 200 W and then increasing. As the rf power increases from 0 to 400 W, the electrical resistivity of carbon thin films increases from 12.32 to 16.23 Ω‧μm. This is because the sp2 carbon atoms decrease with increasing the rf power.

APA, Harvard, Vancouver, ISO, and other styles

27

Huang, Syuan-Wen, and 黃宣文. "Simulation Study of Capacitively Coupled Radio Frequency Silane/Hydrogen Plasma Discharges -Effect of Tailored Voltage Waveforms." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/rre4r8.

Full text

Abstract:

碩士
國立清華大學
工程與系統科學系
107
Capacitively coupled plasma (CCP) has been widely employed for etching and deposition processes. The purpose of this study is to investigate the effect of Tailored Voltage Waveforms (TVWs) on the plasma characteristics of SiH4/H2 plasma, a fluid model based numerical simulation analysis is employed to investigate the fundamental discharge characteristics of the basic physical and chemical mechanisms occurring in the plasma reactor. The TVWs in this study divided into two categories: consist of two frequencies and four frequencies. The first type of TVWs are consist of two equal-voltage sine waves, which are the fundamental frequency 13.56 MHz and the second harmonic frequency 27.12 MHz. Different waveforms can be generated by tuning the relative phase between two frequencies. When the absolute values of positive and negative extremes in TVWs are different, the voltages across the two sheaths are different. At the phase θ = 45° and θ =135°, the difference between the absolutes of positive and negative extreme is maximum. Define these waveforms are V45 and V135, when phase angle are 45 and 135 degree. Simulation results show that when the waveform is V45, the sheath voltage in front of ground electrode is 63 and 49% lower than V135 and single frequency 13.56 MHz, respectively. It is because of the voltage in front of powered is bigger, resulting in higher electron temperature and power density at the side of power electrode. Due to the sheath voltage in front of ground electrode is smaller, thus decrease the potential gradient and ion bombardment effect. In addition to the analysis of the plasma characteristics. This study also analyzes the flux ratio of SiH2/SiH3 and H/SiH3 reaching the substrate. Simulation results showed that the SiH2/SiH3 ratio decreased approximately 50% when the waveform is V45 compared to V135. This is because the electron temperature at the ground electrode is lower when the waveform is V45, which in turn reduces the rate of formation of SiH2. However, the H/SiH3 ratio reaching the substrate is within 10% of the V135 and the single frequency 13.56 MHz. Since the defect density and crystallinity of the film directly proportional to flux ratio of SiH2/SiH3 and H/SiH3, respectively, the simulation results show that TVWs V45 can reduce the defect density in the film without affecting the crystallinity. The second type of TVWs consists of 13.56MHz and its second, third and fourth harmonic frequencies. When θ is 0 and π, the waveform define as “peak” and “valley”. Comparing with V45 and V135, these waveforms having a larger difference ratio between the absolute values of the positive voltage and the negative voltage. Simulation results show that the ion energy is the smallest in waveform “peak”, and the SiH2/SiH3 flux ratio reaching the substrate is 10% and 40% lower than V45 and single frequency 13.56 MHz, respectively. Therefore, the simulation results show that TVWs "peak" can reduce the defect density in the film but does not affect the crystallinity compared to V45 and single frequency 13.56 MHz. Finally, TVWs "peak" simulation results show that the decrease of flux ratio SiH2/SiH3 can explain the microstructure ratio decrease in the literature [3], so the film quality improve under the TVWs “peak”.

APA, Harvard, Vancouver, ISO, and other styles

28

Heil, Brian George [Verfasser]. "Effects of the dynamic interaction between the plasma sheaths and bulk on electron heating in capacitively coupled radio-frequency discharges / von Brian George Heil." 2008. http://d-nb.info/990400093/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Kadetov, Victor A. [Verfasser]. "Diagnostics and modeling of an inductively coupled radio frequency discharge in hydrogen / von Victor Anatolievich Kadetov." 2004. http://d-nb.info/972011854/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Bandyopadhyay, Mainak [Verfasser]. "Studies of an inductively coupled negative hydrogen ion radio frequency source through simulations and experiments / Mainak Bandyopadhyay." 2004. http://d-nb.info/972317309/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Peng, Chia-Lin, and 彭嘉玲. "Low Temperature Growth of Sic Thin Films on Si by High Frequency Inductively Coupled Plasma Enhanced Chemical Vapor Deposition." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/93346967550492063038.

Full text

Abstract:

碩士
國立中山大學
物理學系
86
In this work, we set up an inductively-coupled-plasma-enhance-chemical-vapor-deposition system and grow SiC thin film on Si(1OO) and Si(l13) at low temperature and high frequency. The source gases were SiH4, CH4, and the gas mixed with Ar95% and H25%. The influence of the growth of thin films from different source gases flow ratio, different plasma RF power, different plasma RF frequency and different substrate temperature have been studied. By FTIR spectroscopy investigation, the carbon content on the thin films increases for more CH4 flow, higher frequency of Rf plasma and higher power of RF plasma during the deposition. For higher substrate temperature, the hydrogen content on the thin film decreases but the oxygen content on the thin film increases. The C/Si atom ratio on the thin films has been analyzed by EPMA. All samples were etched by the solution mixed with HF48%:HN0365%=10:3 As C/Si atom ratio of the thin films is above 0.267, Despite of that Si substrate is etched, the SiC film is acid resistive and can remain a smooth and reflective surface. XRD analyses show these thin films containing both of the SiC and Si amorphous structures. TEM analyses reveal that on the thin film the crystalline structures exist, when the C/Si atom ratio was above 0.515.

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Radio frequency inductively-coupled plasma'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles