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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Ion bombardment induced compositional changes in compound semiconductor surfaces by XPS combined with LEISS

Wei, Yu January 1995 (has links)
No description available.

Study on Impedance Matching for RF Sputtering Optimization

Tsou, Chu-Hua 02 August 2007 (has links)
In this study, we propose to investigate the variation of impedance,energy transfer from the RF generator to the discharge is not perfect, and then to improve the sputtering efficiency. For the deposition of insulating film by sputtering technique, the external factors such as input RF power,gar pressure and gas flow rate, and the internal parts of sputtering system such as sputtering target, substrate, and the structure of internal wells of chamber, lead to deviate sputtering parameters such as the DC bias on substrate, ion density in the plasma, and the capacitance of the sheath of glow discharge. All of the factors introduce larger deviations of impedance matching into the sputtering system, that results in decrease the efficiency of film deposition and/or induce re-sputtering phenomena.Comparisons are made with various matching networks applied in real RF sputtering systems. The networks, L-type is choose as the impedance matching network of the RF sputtering system for investigation, is analytically studied in their interaction with the experimental device.From the characteristics of L-type studied, in case of numerical values are deduced and used for the optimizing control the impedance matching network. Finally, by using this technology of impedance matching network, the optimizing sputtering efficiency is achieved and that can enhance the stability of equipment and increase the sputtering rate.

Study on RF Sputtering system

Chang, Ying-Che 25 July 2008 (has links)
In this study, the RF sputtering system has been investigated comprehensively. Firstly, the relationship among the thickness of dark space, DC bias and electrode area under RF discharge is discussed. The impedance matching network of RF sputtering system, the configuration of glow discharge and their related electrical parameters are introduced and illustrated. The network theorem is used to calculate the loading impedance of RF sputtering system and to design an impedance matching circuit. And then the equivalent circuit of sheath and plasma in parallel plate RF discharge is analyzed. The characteristics of gas discharge of RF sputtering system are discussed, which includes the capacitance, resistance and conductivity on different pressure and magnetic field. Due to RF sputtering system usually driven at 13.56 MHz (this is an open frequency), we also considered how to avoid the radio frequency interference. In addition, the electrical characteristics of parallel plate RF discharge are revealed under argon atmosphere, and some of the general relationships between the various measured and determined parameters are also described. Finally, the difference between real system and ideal system are reported, and how to design a system which is rugged and reliable and can be operated, literally, in ¡¨push-button¡¨fashion, has been described in detail.

Theory of sputtering

Mendiola, F. A. January 1958 (has links)
Thesis (M.S.)--University of Michigan, 1958.

Optimisation of a closed-field unbalanced magnetron sputter process : titanium aluminium nitride

Perry, Duncan January 1995 (has links)
No description available.

Contribution à l'étude expérimentale et théorique des cristaux photoniques unidimensionnels hybrides à base de HMDSO et de silicium / Contribution to the experimental and theoretical study of hybrid one-dimensional photonic crystals based on HMDSO and silicon

Amri, Raja 06 October 2017 (has links)
On s'est intéressé dans ce travail à l'élaboration, la caractérisation et la modélisation des propriétés optiques d'une nouvelle génération de cristaux photoniques hybrides à une dimension à base d'un composé organique l'hexaméthyldisiloxane dilué dans l'oxygène ou l'azote, et pur en alternance avec le silicium. Après un bref rappel sur l'historique des cristaux photoniques, et leur originalité qui réside en l'existence de bandes interdites photoniques (BIP) qui sont à la base de leurs applications potentielles dans la communication optique et l'optoélectronique. Nous avons ensuite présenté les matériaux de base utilisés pour l'élaboration de nos cristaux photoniques et qui sont: l'hexaméthyldisiloxane (HMDSO) et le silicium, qu'on a déposé en couches minces par les techniques de PECVD et de pulvérisation cathodique magnétron RF. La composition de ces couches a été analysée par spectroscopie infrarouge à transformé de Fourrier et leurs indices de réfraction déterminés par spectroscopie de transmission et de réflexion. Les deux premiers cristaux photoniques hybrides sont issus de même matériaux organiques le HMDSO qu'on a dilué respectivement avec l'oxygène et l'azote. Pour le premier cristal nous avons fait varier le flux d'oxygène jusqu'à obtenir des nouvelles phases formées de HMDSO et SiO2. Pour le deuxième cristal nous avons dilué le HMDSO avec l'azote en faisant varier la puissance RF de dépôt jusqu'à obtenir deux phases formées de SiCxNyOzH et -Si3N4. Les deux cristaux photoniques sont ainsi de matériau présentant un bon contraste d'indice propice à l'émergence de la bande interdite photonique. Le troisième cristal photonique hybride est quant à lui constitué des couche de HMDSO pur alternées avec des couches de silicium. Nous avons interprété les résultats expérimentaux à l'aide d'un modèle théorique basé sur la méthode de matrice de transfert. Enfin nous avons étudié dans les trois cristaux photoniques l'effet d'incorporation des défauts et nous avons montré l'existence de mode localisé à l'intérieur de la bande interdite photonique / In this work, we focused on the elaboration, characterization and modelization of the optical properties of a new generation of one-dimensional hybrid photonic crystals based from an organic compound hexamethyldisiloxane diluted in oxygen or nitrogen, and pure alternating with silicon. After a brief review of the history of photonic crystals, their originality lies in the existence of photonic band gaps (BIPs) which are the basis of their potential applications in optical communication and optoelectronics. Then we presented the basic materials used for the production of our photonic crystals, which are: hexamethyldisiloxane (HMDSO) and silicon, which have been deposited in thin layers by PECVD and RF magnetron sputtering techniques. The composition of these layers was analyzed by Fourrier transform infrared spectroscopy and their refractive indixes determined by transmission and reflection spectroscopy. The two hybrid photonic crystals were obtained from the same organic materials HMDSO which were diluted with oxygen and nitrogen, respectively. For the first crystal we have varied the flow of oxygen and we obtain a new phases formed of HMDSO and SiO2. For the second crystal we have diluted the HMDSO with nitrogen by varying the RF deposition power until two phases are formed of SiCxNyOzH and -Si3N4. These two photonic crystals are thus materials presenting a good contrast of index leads to the emergence of the photonic band gap. The third hybrid photonic crystal consists of layers of pure HMDSO alternating with layers of silicon. We have interpreted the experimental results using a theoretical model based on the transfer matrix method. Finally, we studied in the three photonic crystals the effect of incorporation of the defects and we have shown the existence of located mode within the photonic band gap

Studies of glow discharge oscillations and jet-enhanced cathodic sputtering

Zhu, Zhubiao 22 January 1996 (has links)
Three aspects of glow discharges have been studied: glow discharge oscillations, sputtering, and coupling between cathode and anode regions the two most important regions in a glow discharge. Cathode and anode processes are tightly coupled by electron and ion coupling effects. Both electron and ion coupling effects were observed by studying excited Ar atoms in the cathode and anode regions and observing laser-induced space charge variations and the optogalvanic effect. Laser-induced space charge variations in the glow discharge were observed by the change in potential of an electrical probe. This signal, called the optopotential signal, provides useful information about the cathode and anode processes, and may become another useful spectroscopic detection method. Glow discharge oscillations are old phenomena but our mechanistic understanding of the processes involved continues to grow. A mechanism study is important especially now since a new type of sensitive GC detector is being developed based on this phenomenon. A SPAN model of glow discharge oscillation is proposed: source formation, propagation, accumulation, and neutralization of space charges. Electrode coupling couples the neutralization and source formation processes thus completing the feedback loop necessary for some of the observed oscillations to occur. Four modes of oscillations were found. Emission, space potential and current monitoring, and forced oscillations were used to monitor and identify the mechanisms. Studies of cathodic sputtering with gas flow rates up to 2.13 L/min/jet were carried out in an Atomsource sputtering atomizer with Ar as the jet gas and Cu as the cathode sample. These flow rates are 20-fold greater than those normally used and were found to increase net sputtering yield significantly. A fourfold increase in net sputtering yield was observed when the number of jets in use was decreased from six to one, with the gas flow rate and other conditions held constant. Possible explanations for these effects are offered. / Graduation date: 1996

Quantum Well Intermixing in Symmetric Multiple Quantum Well Structures by Using ICP-RIE and SiO2 Sputtering

Chang, Heng-Jui 30 July 2007 (has links)
In this thesis, we combined inductively coupled plasma reactive ion etching (ICP-RIE) and SiO2 sputtering to enhance quantum well intermixing (QWI). The samples used in this study were grown by molecular beam epitaxy (MBE) and metal organic chemical vapor deposition (MOCVD) on InP substrates. MBE sample consists of three In0.53Ga0.47As quantum wells, and the other consists of three In0.77Ga0.23As0.79P0.21 quantum wells. Ar+ bombardment by ICP-RIE was the first process step, and then a 300 nm SiO2 capping layer was sputtered upon the samples. The processed samples were subject to rapid thermal annealing. The properties of quantum wells after annealing were determined by photoluminescence (PL) measurement. The In0.53Ga0.47As/In0.53Ga0.26Al0.21As structure was used to design a series of experiments. First, we observed that the amount of blueshift increased with ICP-RIE time increased. ICP-RIE for 8 minutes was the optimum resulting in a bandgap blueshift of 60 nm, leaving a distance of about 200 nm between QWs and the SiO2 interface. The PL blueshift was directly ascribed to QWI caused by compositional interdiffusion between QWs and barriers. To determine how ICP-RIE affects QWI, we used H3PO4 solution to etch samples to the depth that was around 200 nm away from the QWs, and then coated by a sputtered SiO2 layer. Under 700¢J annealing, it gave rise to a blueshift of only 18 nm. And we also proved that the sputtered SiO2 capping layer provided an extra amount of bandgap blueshift. After the mechanism of QWI combining ICP-RIE and SiO2 sputtering was established, we applied this QWI process in In0.77Ga0.23As0.79P0.21/In0.57Ga0.43As0.64P0.36 material system, and we obtained a maximum amount of blueshift of 90 nm in this study.

Measurement setup for High Power Impulse Magnetron Sputtering

Sveinsson, Ólafur Björgvin January 2011 (has links)
Recently material physics group at Science Institute of University of Iceland has been using reactive sputtering to grow thin films used in various research projects at the institute. These films have been grown using dc sputtering which has been proven a very successful method. High power impulse magnetron sputtering or HiPIMS is an new pulsed power sputtering method where shorter but high power pulses are used to sputter over lower steady power. The project resulted in a functional system capable of growing thin films using HiPIMS. Thin films grown with high power pulses have a higher film density and other more preferable properties compared to films grown using direct current magnetron sputtering.

High quality ITO films deposited by Radio-Frequency magnetron sputtering for display applications

Ma, Hung-jen 13 June 2005 (has links)
Indium tin oxide (ITO) films were deposited onto the glass substrate by rf reactive magnetron sputtering method. Deposition was performed by changing processing conditions, such as rf power, process pressure and substrate temperature. The structural, optical and electrical properties of ITO films have been characterized by X-ray diffraction, optical transmittance and sheet resistance. In the process of ITO deposition, we change rf power and fix process pressure at room temperature. And we change process pressure after finding low sheet resistance by changing rf power at room temperature. The low sheet resistance of 35 £[/¡¼ was obtained at room temperature. In addition, we change the substrate temperature while keeping the same rf power and process pressure. When the temperature is 400¢J, the sheet resistance as low as 6.98 £[/¡¼ was obtained. The diffraction peaks on (211), (222), (400), and (440) directions were observed by XRD analysis. Under high temperature (300¢J) deposition the transmittance and diffraction peaks of the films were found to change with different rf power and process pressure. However, the sheet resistances are about the same during the interest for both rf power and process pressure. The UV-visible spectra indicate that the optical transmittance of all the films is between 65 % ~ 90 % at visible range.

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