Thesis--M. Phil., University of Hong Kong.

published_or_final_version / Physics / Master / Master of Philosophy

No description available.

In this project, thin films are being manufactured by different methods in a thin film deposition set-up and subsequently characterized. This is done in order to determine if the set-up is capable of producing films of sufficient quality to be used for research purposes in the ion physics group of the division of applied nuclear physics at Uppsala University. Both copper and silver films are manufactured by magnetron sputtering deposition. Copper films are also manufactured by evaporation deposition. Deposition is made on Si(001) substrates. The films are analyzed with Rutherford Backscattering Spectrometry (RBS) and Time of Flight- Elastic Recoil Detection Analysis (ToF-ERDA). Results show that the deposition rate of the set-up is much faster compared to the one provided by the manufacturer of the set-up. The purity of the films i.e. the concentrations of the contaminants are found to be in an acceptable range for research applications with an average oxygen contamination of <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?1.53%20%5Cpm%200.05%20%25" /> and carbon contamination of <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?0.53%20%5Cpm%200.02%20%25" /> for sputtered copper films. Sputtered silver films were found to have an oxygen contamination of <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?0.28%20%5Cpm%200.012%20%25" /> and a carbon contamination of <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?0.41%20%5Cpm%200.023%20%25" />. Evaporated copper films were found to have an oxygen contamination of <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?0.45%20%5Cpm%200.018%20%25" /> and carbon contamination of <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?0.31%20%5Cpm%200.013%20%25" />. Traces of gold (<img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%5Cprec%200.5%20%25" />) were found exclusively in the sputtered films. Trace amounts of hydrogen could also be detected in both sputtered and evaporated films. The evaporated films are found to show lower contamination by oxygen than the sputtered films, but the manufacturing process employed in this study of evaporated films is not suitable to use for producing thin films of specific thicknesses as there is insufficient data to find a deposition speed. Overall, the set-up is capable of producing thin films with a sufficient quality for it to be used by the department when producing thin films for research. / I det här projektet produceras tunnfilmer med olika metoder i en uppställning för tunnfilmsdeposition och karaktäriseras sedan för att bedöma om maskinen är kapabel att producera filmer av tillräckligt bra kvalitet för att kunna användas i forskningssyften inom jonfysikgruppen på avdelningen för tillämpad kärnfysik på Uppsala Universitet. Både koppar och silverfilmer produceras med magnetronsputtring. Kopparfilmer produceras också med resistiv förångning. Deposition sker på Si(001)-substrat. Filmerna analyseras med Rutherford Backscattering Spectrometry (RBS) och Time of Flight- Elastic Recoil Detection Analysis (ToF-ERDA). Resultaten visar att depositionshastigheten för maskinen är snabbare än det som angetts av företaget som producerar maskinen. Renheten hos filmerna, dvs. koncentrationen av föroreningar, finnes vara inom en acceptabel nivå för forskningstillämpningar med en genomsnittlig syrekontamination på <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?1.53%20%5Cpm%200.05%20%25" /> och kolkontamination på <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?0.53%20%5Cpm%200.02%20%25" /> för sputtrade kopparfilmer. Sputtrade silverfilmer finnes ha en syrekontamination på <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?0.28%20%5Cpm%200.012%20%25" /> och en kolkontamination på <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?0.41%20%5Cpm%200.023%20%25" />. Förångade kopparfilmer finnes att ha en syrekontamination på <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?0.45%20%5Cpm%200.018%20%25" /> och en kolkontamination på <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?0.31%20%5Cpm%200.013%20%25" />. Spår av guld (<img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%5Cprec%200.5%20%25" />) hittades enbart i sputtrade filmer. Spår av väte kunde också hittas i både sputtrade och förångade filmer. De förångade filmerna finnes ha lägre syrekontamination än de sputtrade filmerna, men tillverkningsprocessen som används i projektet vid tillverkning av förångade filmer är inte lämplig att använda i produktion av tunnfilmer med specifika tjocklekar då det saknas data för att kunna hitta en depositionshastighet. Totalt sett är uppställningen kapabel att producera filmer av adekvat kvalitet för att de ska kunna användas inom avdelningen för produktion av filmer för forskning.

Graduation date: 1993

Deposition of thin material films by sputtering is an increasingly common process in the field of silicon (Si)-based photovoltaics. One of the recently developed sputter-deposited materials applicable to Si photovoltaics comprises Si nanocrystals (NCs) embedded in a Si-based dielectric. The particular case of Si nanocrystals in a Silicon Dioxide (SiO2) matrix was studied by fabricating metal-insulator-semiconductor (MIS) devices, in which the insulating layer consists of a single layer of Si NCs in SiO2 deposited by sputtering (Si:NC-MIS devices). These test structures were subjected to impedance measurements. The presence of Si NCs was found to result in two distinct capacitance peaks. The first of these peaks is attributable to the small signal response of states at the insulator/substrate interface, enhanced by the presence of fixed charge associated with the NC layer. The second peak, which occurs without precedent, is due to external inversion layer coupling, in conjunction with a transition between tunnel-limited and semiconductor-limited electron current. Si:NC-MIS devices are also potential test structures for energy-selective contacts, based on SiO2/Si NC/SiO2 double barrier structures fabricated by sputtering. Using a one-dimensional model, current-voltage (I-V) curve simulations were performed for similar structures, in which the Si NCs are replaced by a Si quantum well (QW). The simulations showed that for non-degenerately doped Si substrates, the density of defects in the SiO2 layers can strongly influence the position of I-V curve structure induced by QW quasi-bound states. Passivation of crystalline Si (c-Si) surfaces by sputter-deposited dielectric films is another major application of sputtering for Si photovoltaics. This application was explored for the cases of sputtered SiO2 and hydrogenated Silicon Oxy-Carbide (SiOC:H). For the case of sputtered SiO2, an effective surface recombination velocity of 146 cm/s was achieved for an injection level of 1E15 cm???3. The investigated SiOC:H films were found to be unsuitable for surface passivation of Si, however their passivation performance could be slightly improved by first coating the Si surface with a chemically-grown or sputtered SiO2 layer. The investigations performed into specific aspects of sputter-deposited SiO2, Si NCs, and SiOC:H have highlighted important properties of these films, and confirmed the effectiveness of sputtering as a deposition technology for Si photovoltaics.

Thesis (Ph.D.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references.

Thesis (Ph. D.)--University of Hong Kong, 2008. / Also available in print.

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 65-69). Also available on the World Wide Web.

Made available in DSpace on 2014-06-11T19:23:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-06-23Bitstream added on 2014-06-13T19:29:31Z : No. of bitstreams: 1 carvalho_av_me_bauru.pdf: 1153959 bytes, checksum: d1140cdf287a17bba3b0a2bcf3f995eb (MD5) / Descreve-se a preparação de várias amostras de filmes finos de Nitreto de Gálio (GaN), depositados sobre diferentes tipos de substratos pela utilização da técnica de RF-Magnetron Sputtering Reativo, utilizando-se atmosfera de nitrogênio ('N POT. 2') com diferentes temperaturas de substrato (< 400ºC). As amostras foram caracterizadas estruturalmente pelo uso da técnica de difração de raio-X (DRX), permitindo a obtenção de informações sobre tamanhos de cristalito, padrões de texturação e parâmetros de rede. A ocorrência de textura de orientação bem definida e a relação desta com as condições do alvo utilizado são analisadas no trabalho. / The preparation of several samples of Gallium Nitride (GaN) thin films, deposited onto different kinds of substrates by Reactive RD - Magnetron Sputtering, in pure Nitrogen ('N POT. 2') atmosphere with different substrate temperatures (< 400ºC) is described. The samples were structurally characterized by the use of X-ray diffraction, allowing obtain of information about cristalite size, texture pattern, and lattice parameters. The occurence of orientation texture and its relationship with target conditions are analysed.