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Diagnostics of plazma in the deposition sources using the Langmuir probes
Šedivý, Petr ; Kousal, Jaroslav (advisor) ; Kylián, Ondřej (referee)
This experimental work is concerned with measurement of elementary characteristics of plasma - potential of plasma, electron temperature and density of particles. As research methods were selected the Langmuir probes - especially the single probe. At the beginning of the thesis there are explained shortly the elementary characteristics of plasma and the procedure of determination particular parameters of the plasma from the volt-ampere characteristics of the probe. The third chapter is focused on description of the experiment, the probe, the apparatus and its control. Plasma measured within this work originated from the new hollow magnetron which will serve as future source of nanoparticles. Results of the work are focused on the description of individual parameters of the plasma in dependence on other variables such as the magnetron power, pressure of gas, spatial dependence or presence of additional auxiliary magnetic field.
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Diagnostics of thin layer deposition using dimethylphenylsilane monomer
Procházka, Michal ; Kudrle, Vít (referee) ; Krčma, František (advisor)
The aim of this thesis is a study of processes during organosilicone thin film deposition via plasma polymerization. Recently, thin films are the most expanding way of surface modification of materials. They are used as protective coatings, functional layers, they can increase or decrease adhesion to different compounds (e.g. water), or just improve mechanical properties of bulk materials. Plasma polymers, which are not known so long, are a modern trend in evolution of thin film deposition. They have perfect adhesion to the substrate and they are highly resistant against most of chemical compounds. Their structure is quite different from the structure of classical polymers. Recently, organosilicon compounds are used as precursors for plasma polymers because silicon built in the structure of plasma polymer allows thin film deposition on glass substrate and the organic part of monomer gives us infinite possibilities of modification. In our case dimethylphenylsilane (DMPS) was used as a monomer. Various RF low pressure discharges were used during this study. Plasma diagnostic was performed by optical emission spectroscopy of inductive coupled plasma. This method allows us to determine plasma composition during the deposition process. Thus we can predict the composition of deposited thin film according to input parameters. From relative populations of fragments we are able to find out optimal conditions for deposition process. We can also calculate temperature of particles in plasma which gives us some information about particle energies. The first part of the study deals with the identification of particles (fragments) created by fragmentation of monomer in plasma environment. We successfully identified hydrogen atomic lines of Balmer’s series in the spectra. Many rotational lines of hydrogen molecule were also detected. Atomic carbon occurred only in small amount. Much more carbon was detected in the form of CH radical. We also found some weak lines connected to atomic silicon. When we used a mixture of DMPS and oxygen, OH radical and O2+ were present in spectra. Next, optimal settings of deposition were determined for particular fragments from relative intensities of these fragments in optical emission spectra. Using this information we are able to set up the process to deposit thin films of desired composition and properties. We calculated electron temperature from intensities of hydrogen lines in Balmer’s series. Rotational temperature was obtained from CH radical intensity. Unfortunately, there was no convenient radical from which intensity we would be able to calculate vibrational temperature. All results and information obtained during the research can be used in industrial plasma polymerization processes and development of new coatings and functional thin films. Other studies on DMPS or similar monomer may also be realized to get more knowledge about processes in plasma and this thesis could serve as a basis for further research. Moreover, this study is a part of an international project. The aim of this project is to study processes during plasma polymerization both theoretically and practically. Once finished, the project and its results will be presented in scientific literature and at international conferences.
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Characterization of plasma during organosilicone thin film deposition using haxamethyldisiloxane monomer
Blahová, Lucie ; Mazánková, Věra (referee) ; Krčma, František (advisor)
The aim of this thesis is plasma diagnostic during deposition of thin films based on organosilicones. Hexamethyldisiloxane was used as a precursor for plasma deposition in the presence of oxygen, and the diagnosis was performed by using optical emission spectroscopy. The theoretical part summarizes the basic characteristics of plasma and processes occurred at plasma polymerization and deposition. It also deals with thin films and their use in coating materials. A relatively large part is devoted to the specification of the physical-chemical nature of the used analytical method – optical emission spectroscopy. Finally, the principles of rotational, vibrational and electron temperature calculations are described. The contemporary deposition process was carried out in continuous and pulsed mode of radiofrequently excited capacitively coupled discharge. The effects of monomer flow rate, plasma power and duty cycle on the deposition process were studied. In the individual spectra, atomic hydrogen lines of Balmer’s series as well as an atomic oxygen line were identified. Molecular bands of CO have been identified as Angstrom’s system and 3. positive system. In the case of the identified fragments, the intensity dependencies on the monomer concentration in mixture, plasma power and duty cycle were detected. Electron temperature of plasma was also calculated using the relative intensities of atomic hydrogen lines of Balmer’s series. Vibrational and rotational temperature could not have been determined because no suitable fragments for their determination were found in the spectrum. Based on findings mentioned above, partial composition of plasma and some of its properties were estimated. The subject of the further research will be determination of the exact content and structure of the thin films and investigation of other plasma characteristics. Plasma deposition is influenced by many factors, and the study of their optimal combination for the most efficient deposition process is a goal for the future research.
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