|
|
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.
|
|
|
Functional Tungsten-based thin films and their characterization
Košelová, Zuzana ; Horáková, L. ; Sobola, Dinara ; Burda, Daniel ; Knápek, Alexandr ; Fohlerová, Z.
Anodizing is a technique by which thin oxide layers can be formed on a surface. Thin oxide layers have been found to be useful in a variety of applications, including emitters of electrons. Tungsten is still a common choice for cold field emitters in commercial microscopy applications. Its suitable quality can be further improved by thin film deposition. Not only the emission characteristic can be improved, but also the emitter operating time can be extended. Tungsten oxide is known for its excellent resistance to corrosion and chemical attack due to its stable crystal structure and strong chemical bonds between tungsten and oxygen atoms. Many techniques with different advantages and disadvantages have been used for this purpose. Anodization was chosen for this work because of the controllable uniform coverage of the material and its easy availability without the need for expensive complex equipment. The anodizing process involves applying an electrical potential to tungsten while it is immersed in an electrolyte solution. This creates a thin layer of tungsten oxide on the surface of the metal. The thickness and properties of the resulting oxide layer can be controlled by adjusting the anodization conditions, such as the electrolyte solution, voltage, and the duration of the process. In this work, H3PO4 was used as the electrolyte to test whether these tungsten oxide layers would be useful for electron emitters, for use in electron guns and other devices that require high-quality electron emitters. The properties were evaluated using appropriate techniques. In general, anodization of tungsten to form thin layers of tungsten oxide layers is a promising technique for producing high quality electron emitters.
|
|
|
Attaining surface homogeneity in the deposition of complex layer systems
Žídek, Karel
We report on a procedure of optimization of a thin-film deposition process with respect to the best attainable layer homogeneity on a large deposited surface. By using a deposition mask and rotation of the deposition calotte, we reach the homogeneity of ± 0.5% for samples with the diameter up to 5 cm. Furthermore, we investigate the effect of substrate tilt and of a deposition on a curved lens surface with respect to homogeneity of the deposited layer.
|
|
| |
|
|
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.
|
guest ::
