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[{"key": "dc.contributor.advisor", "value": "Maasilta, Ilari", "language": null, "element": "contributor", "qualifier": "advisor", "schema": "dc"}, {"key": "dc.contributor.author", "value": "R\u00e4s\u00e4nen, Eetu", "language": null, "element": "contributor", "qualifier": "author", "schema": "dc"}, {"key": "dc.date.accessioned", "value": "2025-06-17T07:35:48Z", "language": null, "element": "date", "qualifier": "accessioned", "schema": "dc"}, {"key": "dc.date.available", "value": "2025-06-17T07:35:48Z", "language": null, "element": "date", "qualifier": "available", "schema": "dc"}, {"key": "dc.date.issued", "value": "2025", "language": null, "element": "date", "qualifier": "issued", "schema": "dc"}, {"key": "dc.identifier.uri", "value": "https://jyx.jyu.fi/handle/123456789/103655", "language": null, "element": "identifier", "qualifier": "uri", "schema": "dc"}, {"key": "dc.description.abstract", "value": "l\u00e4mm\u00f6njohtumista voidaan hallita fononikiteen (PnC) avulla, joka on yksi-, kaksi- tai kolmiulotteinen periodinen rakenne. Fononikiteen geometrialla on merkitt\u00e4v\u00e4 vaikutus sen l\u00e4mm\u00f6njohtavuuteen.\nFononikiteen valmistus on eritt\u00e4in tarkkaa ja haastavaa. Pienetkin viat tai ep\u00e4puhtaudet voivat heikent\u00e4\u00e4 n\u00e4ytteen laatua. Valmistusprosessi sis\u00e4lt\u00e4\u00e4 useita nanoteknologiassa yleisesti k\u00e4ytettyj\u00e4 laitteita. T\u00e4ss\u00e4 pro gradu -tutkielmassa kehitet\u00e4\u00e4n yksityiskohtainen valmistusprosessi heksagonaalisen, rei\u2019itetyn fononihilan tuottamiseksi hyvin pienell\u00e4 jaksollisuudella. Fononihilan valmistukseen piinitridille (SiN) k\u00e4ytettiin kahta eri menetelm\u00e4\u00e4. Ensimm\u00e4isess\u00e4 menetelm\u00e4ss\u00e4 k\u00e4ytettiin alumiinioksidikalvoa (Al2O3) kovana maskina etsausprosessissa. Toisessa menetelm\u00e4ss\u00e4 k\u00e4ytettiin ainoastaan positiivista resisti\u00e4 maskina. Alumiinioksidimaski mahdollistaa ohuemman maskikerroksen kuin resisti, mik\u00e4 parantaa etsausaineen p\u00e4\u00e4sy\u00e4 substraatin pinnalle.\nMolemmilla menetelmill\u00e4 valmistettiin useita n\u00e4ytteit\u00e4, joiden hilavakiot vaihtelivat v\u00e4lill\u00e4 200\u2013350 nm. 280 nm hilavakiolla t\u00e4ytt\u00f6suhde oli 46 %. T\u00e4ytt\u00f6suhteen havaittiin kasvavan suuremmilla hilavakioilla. Alumiinioksidimaskilla valmistetut n\u00e4ytteet etsaantuivat liikaa, mik\u00e4 johti hilarakenteen poistumiseen. Sen sijaan resistimaskilla valmistetut n\u00e4ytteet onnistuivat hyvin, ja niiss\u00e4 havaittiin suorat sein\u00e4m\u00e4t ja v\u00e4h\u00e4inen pinnan karheus.\n", "language": "fi", "element": "description", "qualifier": "abstract", "schema": "dc"}, {"key": "dc.description.abstract", "value": "In semiconductors and insulators, heat is primarily transported via phonons. This phonon thermal transport can be engineered using a phononic crystal (PnC), a periodic structure in one, two, or three dimensions. The geometry of the phononic crystal plays a significant role in determining its thermal conductivity.\nThe fabrication of phononic crystals is a highly precise and challenging process. Even minor defects or contamination can compromise the integrity of the sample. The fabrication workflow involves several advanced tools commonly used in nanotechnology. In this master\u2019s thesis, a detailed fabrication process is developed to produce a hexagonal hole-patterned phononic lattice with very low period. Two fabrication approaches were employed to create the phononic lattice on silicon nitride (SiN). The first method utilized an aluminum oxide (Al2O3) thin film as a hard mask during the etching process. The second method relied solely on a positive resist as the etching mask. The aluminum oxide mask allows for a thinner masking layer compared to the resist, thereby facilitating more effective access of the etching agent to the substrate surface. \nMultiple samples were fabricated using both methods, with lattice constants ranging from 200 nm to 350 nm. For a lattice constant of 280 nm, the hole filling factor was measured at 46 %. The filling factor was found to increase with larger lattice constants. However, samples fabricated with the aluminum oxide mask experienced over-etching, which led to the complete removal of the lattice structure. In contrast, the resist-based method yielded successful results, producing straight sidewalls with minimal surface roughness.", "language": "en", "element": "description", "qualifier": "abstract", "schema": "dc"}, {"key": "dc.description.provenance", "value": "Submitted by Jutta Aalto (aalto@jyu.fi) on 2025-06-17T07:35:48Z\nNo. of bitstreams: 0", "language": "en", "element": "description", "qualifier": "provenance", "schema": "dc"}, {"key": "dc.description.provenance", "value": "Made available in DSpace on 2025-06-17T07:35:48Z (GMT). No. of bitstreams: 0\n Previous issue date: 2025", "language": "en", "element": "description", "qualifier": "provenance", "schema": "dc"}, {"key": "dc.format.extent", "value": "46", "language": null, "element": "format", "qualifier": "extent", "schema": "dc"}, {"key": "dc.language.iso", "value": "eng", "language": null, "element": "language", "qualifier": "iso", "schema": "dc"}, {"key": "dc.rights", "value": "In Copyright", "language": null, "element": "rights", "qualifier": null, "schema": "dc"}, {"key": "dc.subject.other", "value": "Phononic crystal", "language": null, "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "hexagon lattice", "language": null, "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "Silicon nitride", "language": null, "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.subject.other", "value": "fabrication", "language": null, "element": "subject", "qualifier": "other", "schema": "dc"}, {"key": "dc.title", "value": "Holey phononic crystal with ultra low period", "language": null, "element": "title", "qualifier": null, "schema": "dc"}, {"key": "dc.type", "value": "master thesis", "language": null, "element": "type", "qualifier": null, "schema": "dc"}, {"key": "dc.identifier.urn", "value": "URN:NBN:fi:jyu-202506175460", "language": null, "element": "identifier", "qualifier": "urn", "schema": "dc"}, {"key": "dc.contributor.faculty", "value": "Matemaattis-luonnontieteellinen tiedekunta", "language": "fi", "element": "contributor", "qualifier": "faculty", "schema": "dc"}, {"key": "dc.contributor.faculty", "value": "Faculty of Sciences", "language": "en", "element": "contributor", "qualifier": "faculty", "schema": "dc"}, {"key": "dc.contributor.department", "value": "Fysiikan laitos", "language": "fi", "element": "contributor", "qualifier": "department", "schema": "dc"}, {"key": "dc.contributor.department", "value": "Department of Physics", "language": "en", "element": "contributor", "qualifier": "department", "schema": "dc"}, {"key": "dc.contributor.organization", "value": "Jyv\u00e4skyl\u00e4n yliopisto", "language": null, "element": "contributor", "qualifier": "organization", "schema": "dc"}, {"key": "dc.contributor.organization", "value": "University of Jyv\u00e4skyl\u00e4", "language": null, "element": "contributor", "qualifier": "organization", "schema": "dc"}, {"key": "dc.subject.discipline", "value": "Fysiikka", "language": "fi", "element": "subject", "qualifier": "discipline", "schema": "dc"}, {"key": "dc.subject.discipline", "value": "Physics", "language": "en", "element": "subject", "qualifier": "discipline", "schema": "dc"}, {"key": "dc.type.coar", "value": "http://purl.org/coar/resource_type/c_bdcc", "language": null, "element": "type", "qualifier": "coar", "schema": "dc"}, {"key": "dc.rights.copyright", "value": "\u00a9 The Author(s)", "language": "fi", "element": "rights", "qualifier": "copyright", "schema": "dc"}, {"key": "dc.rights.accesslevel", "value": "openAccess", "language": null, "element": "rights", "qualifier": "accesslevel", "schema": "dc"}, {"key": "dc.type.publication", "value": "masterThesis", "language": null, "element": "type", "qualifier": "publication", "schema": "dc"}, {"key": "dc.subject.yso", "value": "fononit", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "nanorakenteet", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "nanotekniikka", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.subject.yso", "value": "puolijohteet", "language": null, "element": "subject", "qualifier": "yso", "schema": "dc"}, {"key": "dc.rights.url", "value": "https://rightsstatements.org/page/InC/1.0/", "language": null, "element": "rights", "qualifier": "url", "schema": "dc"}]
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