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1
Gu, Zheng. "Sublimation growth of AlN-SiC alloys, AlN and ScN bulk crystals, and thermal oxidation of AlN /." Search for this dissertation online, 2006. http://wwwlib.umi.com/cr/ksu/main.
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Entezarian, Majid. "Metallization of AlN." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56793.
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Heat dissipation from silicon chips is becoming critical as a result of increasing circuit density and power applied to these chips. In this regard, aluminum nitride (AlN) is the most promising candidate to be used as a substrate since it possesses high a thermal conductivity and thermal expansion coefficient close to that of silicon. In addition, metal-ceramic interfaces determine the heat dissipation through a circuit. In order to minimize the effect of interfaces, direct bonding (DB) of AlN to Cu was studied. DB process has been reported to provide a low thermal barrier and an interface which is free of thermal fatigue.In this work process parameters of DB were optimized based on time, temperature and thickness of the Cu-foil for Cu-Al$ sb2$O$ sb3$ system in a N$ sb2$ atmosphere containing 500 ppm O$ sb2$ in a temperature range of 1065 to 1075$ sp circ$C. These conditions were then applied to the Cu-AlN system. Wettability of AlN by Cu was studied and improved through oxidation of AlN and modification of Cu by adding 1 at.% O$ sb2$. The activation energy for oxidation of AlN was found to be 94 kJ/mol. It was then shown that direct bonding of Cu to AlN can be performed without any intermediate layer. The average peel strength of AlN-Cu, A$ sb2$O$ sb3$-Cu and AlN-Al$ sb2$O$ sb3$-Cu systems were measured to be 42, 49 and 14.7 MPa, respectively.
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BANAL, RYAN GANIPAN. "MOVPE Growth of AlN and AlGaN/AlN Quantum Wells and their Optical Polarization Properties." 京都大学 (Kyoto University), 2009. http://hdl.handle.net/2433/78005.
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Fuentes, Iriarte Gonzalo. "AlN Thin Film Electroacoustic Devices." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2003. http://publications.uu.se/theses/91-554-5557-3/.
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Taking, Sanna. "AlN/GaN MOS-HEMTs technology." Thesis, University of Glasgow, 2012. http://theses.gla.ac.uk/3356/.
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The ever increasing demand for higher power devices at higher frequencies has prompted much research recently into the aluminium nitride/gallium nitride high electron mobility transistors (AlN/GaN HEMTs) in response to theoretical predictions of higher performance devices. Despite having superior material properties such as higher two-dimensional electron gas (2DEG) densities and larger breakdown field as compared to the conventional aluminium gallium nitride (AlGaN)/GaN HEMTs, the AlN/GaN devices suffer from surface sensitivity, high leakage currents and high Ohmic contact resistances. Having very thin AlN barrier layer of ∼ 3 nm makes the epilayers very sensitive to liquids coming in contact with the surface. Exposure to any chemical solutions during device processing degrades the surface properties, resulting in poor device performance. To overcome the problems, a protective layer is employed during fabrication of AlN/GaN-based devices. However, in the presence of the protective/passivation layers, formation of low Ohmic resistance source and drain contact becomes even more difficult. In this work, thermally grown aluminium oxide (Al2O3) was used as a gate di- electric and surface passivation for AlN/GaN metal-oxide-semiconductor (MOS)-HEMTs. Most importantly, the Al2O3 acts as a protection layer during device processing. The developed technique allows for a simple and effective wet etching optimisation using 16H3PO4:HNO3:2H2O solution to remove Al from the Ohmic contact regions prior to the formation of Al2O3 and Ohmic metallisation. Low Ohmic contact resistance (0.76Ω.mm) as well as low sheet resistance (318Ω/square) were obtained after optimisation. Significant reduction in the gate leakage currents was observed when employing an additional layer of thermally grown Al2O3 on the mesa sidewalls, particularly in the region where the gate metallisation overlaps with the exposed channel edge. A high peak current ∼1.5 A/mm at VGS=+3 V and a current-gain cutoff frequency, fT , and maximum oscillation frequency, fMAX , of 50 GHz and 40 GHz, respectively, were obtained for a device with 0.2 μm gate length and 100 μm gate width. The measured breakdown voltage, VBR, of a two-finger MOS-HEMT with 0.5μm gate length and 100 μm gate width was 58 V. Additionally, an approach based on an accurate estimate of all the small-signal equivalent circuit elements followed by optimisation of these to get the actual element values was also developed for AlN/GaN MOS-HEMTs. The extracted element values provide feedback for further device process optimisation. The achieved results indicate the suitability of thermally grown Al2O3 for AlN/GaN-based MOS-HEMT technology for future high frequency power applications.
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Karlsson, Matilda. "Framställning av multilagerfilmen AlN-HQ." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-176218.
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The method Atomic Layer Deposition, ALD, has been available since the 1970´s and it has opened the possibility to fabricate methods for inorganic thin films on a nanoscale. Later the interest for fabricating organic thin films with Molecular Layer Deposition, MLD, and controlling both the thickness and the composition of the film on a molecular scale. To develop the thin films a bit further a combination of organic and inorganic thin films is fabricated and therefore the best properties of the two types of thin films are combined. The purpose of this bachelor´s thesis was to fabricate the multilayer thin film AlN-HQ on a silicon substrate. It began with a substantial review of the literature and planning of the approach. Followed by the laboratory work with fabricating the thin film by ALD. The laboratory work ended with analyzing the thin films by ATR-FT/MIR (attenuated total reflectance fourier transform mid-infrared spectroscopy) and XRR (X-ray reflectivity). All data provided where summarized and evaluated. An analysis of the thickness of the thin film was attempted with XRR but was not adequate for these samples. For a development of the method fabrication of the multilayer film AlN-HQ the thickness needs to be known. It could probably be analyzed by Scanning Electron Microscopy, SEM, but that type of analysis was not a part of this study.
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DEPARDIEU, GILLES. "Proprietes optiques des nanocomposites al-aln." Paris 6, 1995. http://www.theses.fr/1995PA066580.
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Le developpement rapide de nouveaux materiaux composites est une occasion de mieux comprendre leur interaction avec les rayonnements electromagnetiques. De nombreuses applications en decoulent comme la realisation de capteurs selectifs, de revetements pour des applications esthetiques ou de furtivite. Cette etude presente une synthese des modeles anciens jusqu'aux plus modernes des proprietes optiques des materiaux heterogenes desordonnes. En particulier, sont discutees l'application des theories du groupe de renormalisation et de la percolation, ainsi que les differentes variantes de theories de milieux effectifs. L'etude est menee sur un composite original: l'al-aln. L'importance de la morphologie 3d est soulignee, et celle-ci est prise en compte dans le modele propose, a l'aide d'outils de traitement d'image et de la programmation hyperparallele. Une comparaison theorie - experience permet enfin de valider le nouveau modele de renormalisation optique 3d
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Kaneko, Mitsuaki. "Strain-Controlled AlN Growth on SiC Substrates." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/217172.
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Cannard, P. J. "A study of some AlN related polytypes." Thesis, Bucks New University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234418.
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Wildhack, Stefanie. "Herstellung flüssigphasengesinterter Schichtkomposite aus SiC und AlN." [S.l. : s.n.], 2003. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10806386.
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Cledat-Schneider, Sandrine. "Elaboration et propriétés de composites particulaires AlN-TiB2." Limoges, 1997. http://www.theses.fr/1997LIMO0028.
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Dans le but d'evaluer puis d'optimiser leurs proprietes, des composites ceramiques particulaires aln-tib#2 denses (d#r>99 %) ont ete elabores, sans utilisation d'ajout de frittage, par compression isostatique a chaud de melanges de poudres de nitrure aln et de borure tib#2. L'etude des proprietes thermomecaniques et elastiques a permis de selectionner une composition (tib#2 : 75 mol. % ; aln : 25 mol. %) presentant a l'ambiante des caracteristiques mecaniques optimales. L'utilisation de poudres commerciales de plus faible granulometrie ameliore la resistance a la rupture a l'ambiante et la valeur de 620 mpa est conservee jusqu'a 1100c. Le comportement au fluage en flexion de ce materiau est gouverne par la cavitation. La tenue aux chocs thermiques est toutefois limitee a 340c. La seconde partie concerne l'elaboration d'un composite equimolaire aln-tib#2 dense par reaction exothermique entre une poudre de diborure d'aluminium alb#2 et une poudre de nitrure de titane tin, puis densification. La microstructure est fine et homogene, la taille des grains n'excede pas le micrometre. Les proprietes sont tres faiblement ameliorees par rapport au cas precedent. Enfin, la reactivite des materiaux monolithiques aln et tib#2 et celle du composite equimolaire aln-tib#2 ont ete etudiees par analyse thermogravimetrique en regime dynamique d'oxygene. Le composite equimolaire presente une resistance a l'oxydation intermediaire entre celle du diborure de titane qui debute a 700c et celle du nitrure d'aluminium qui commence a 1000c par la formation d'une phase oxynitrure (al#1#0n#8o#3) precedant celle de l'alumine-. Le piegeage in situ d'une partie de l'oxyde b#2o#3 par le nitrure d'aluminium ou l'alumine conduit a la formation d'aluminoborates al#4b#2o#9 et al#1#8b#4o#3#3, ce qui diminue tres fortement la production des vapeurs corrosives de sesquioxyde de bore qui, dans le cas du borure pur, sont observees des 900c.
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Le, Vaillant Yves-Matthieu. "Etude structurale et spectroscopique d'hétéroépitaxies GaN/AlN/Saphir." Montpellier 2, 1999. http://www.theses.fr/1999MON20063.
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L'heteroepitaxie du nitrure de gallium (gan) est confrontee a l'absence de substrat reellement adapte, conduisant a l'introduction d'une couche de nucleation. Nous avons etudie le mode de recristallisation de cette couche de nucleation en nitrure d'aluminium (ain) au cours de son recuit isotherme a haute temperature. Grace a des techniques de microscopie (microscopie electronique en transmission a haute resolution, microscopie a force atomique) et a la diffraction des rayons x, nous avons mis en evidence une croissance polycristalline hautement orientee en colonnes hexagonales deformees. Pour la premiere fois sur ce type de couche, nous avons applique la methode d'analyse de warren-averbach. Cette analyse de fourier particuliere de la diffraction des rayons x nous a permis d'atteindre quantitativement et statistiquement des tailles et des etats de contrainte caracteristiques des cristallites. Les facteurs impliques dans la coalescence des cristallites sont nombreux (solubilite, microcontrainte, semi-coherence interfaciale, fusion anisotrope), mais l'ensemble de ces mesures nous a permis de prouver un regime lineaire de grossissement des grains pouvant s'apparenter au murissement d'ostwald. Une energie d'activation effective a ete obtenue : 17,3 kj. Mol 1. L'heteroepitaxie de ce materiau a aussi des consequences directes sur ses proprietes optiques. Nous avons etudie les effets de la contrainte biaxiale sur la structure de bande electronique au centre de la zone de brillouin. La resolution de l'equation au hamiltonien par la methode k. P et la simulation des transitions du polariton excitonique d'apres le modele de hopfield nous ont permis de determiner le potentiel du champ cristallin ( 1 = 7,0 mev) ainsi que les parametres de couplage spin-orbite ( 2 = 6,1 mev, 2 = 4,5 mev). L'etude de la photoluminescence de gan a basse temperature (2 k) nous a permis de caracteriser les raies principales : paires donneur-accepteur, bande jaune, bande situee a 3,41 ev, bord de bande. Grace au modele de franck-condon, nous avons determine la loi d'extinction des repliques phonons de transitions donneur-accepteur et obtenu la constante de couplage de huang-rhys : s = 0,6.
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Penner, Jakob. "Lokale Gitterumgebung von Indium in GaN, AlN und InN." [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=985159979.
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Oh, Jae Hoon 1967. "AlN precipitation in dual-phase 3% SI electrical steels." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33341.
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The existing approaches to the detection of precipitation are based on one of the following four techniques: (1) electron microscopy; (2) chemical or electrochemical extraction; (3) the measurement of electrical resistivity; and (4) the analysis of mechanical properties. These techniques can only be used at room temperature on quenched samples. However, the direct measurement of precipitation kinetics at high temperatures is also possible through analysis of the mechanical properties of the specimens.In this work, a creep method was developed and applied to the detection of aluminum nitride precipitation in a dual phase 3% silicon steel. These steels are used in electric power applications, typically as magnetic core materials for transformers, electric motors and generators. Prior to loading, the specimens are solution treated for 20 minutes and then cooled to the test temperature. A constant stress is applied to the sample by means of a computerized MTS machine and the strain is recorded continuously during testing. Microstructural examination revealed that the austenite fraction and morphology and microstructure of the ferrite matrix are quite different depending on whether samples are directly heated or heated and then cooled to the test temperature. The resulting creep rate is sensitive to the occurrence of precipitation; thus the slope of the true strain-log (time) curve decreases immediately after initiation. The precipitation-time-temperature diagrams determined in this way are of classical C shape.
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Yarar, Erdem [Verfasser]. "Inverse-Bilayer AlN/(Fe90Co10)78Si12B10 Magnetoelectric Composites / Erdem Yarar." Kiel : Universitätsbibliothek Kiel, 2017. http://d-nb.info/1149512857/34.
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Ribeiro, Maria Cláudia Badan. "Experiência de luta na emancipação feminina: mulheres na ALN." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/8/8138/tde-26042012-163246/.
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A pesquisa teve como objetivo recuperar as redes de solidariedade formadas por mulheres que mantiveram ou não vínculos orgânicos com a ALN (Ação Libertadora Nacional) e que prestaram os mais diversos tipos de colaboração a essa organização, participando não apenas dos levantamentos para ações armadas ou diretamente de sua execução, mas desempenhando também um papel primordial na retaguarda do movimento armado. A colaboração dessas mulheres foi parte também das transformações que se processaram na sociedade da época com relação à participação da mulher no espaço público. Na militância política, elas também introduziram mudanças na divisão de papéis entre os sexos e ressignificaram sua participação no interior dos grupos nos quais se incorporaram. Sua atividade foi fundamental para garantir a vida de pessoas, bem como permitir a continuação das atividades da organização no Brasil, em especial nos momentos mais repressivos da ditadura. Muito além de pequenos gestos, como se supõe, essas mulheres formaram uma força discreta, que deu aos militantes clandestinos a estabilidade necessária para continuarem na luta.The research aimed to restore the solidarity networks formed by women who maintained or no organic links with the ALN (National Liberation Action), which provided the most diverse types of contributions to that organization, participating not only from surveys or directly to armed actions his execution, but also playing a pivotal role in the rear of the armed movement. The collaboration of these women was also part of the changes which were processed in the society of that time with respect to women\'s participation in public space. In political activism, they also introduced changes in the division of roles between the sexes, and resignify their participation within the groups of which it is incorporated. Its activity was essential to safeguard the lives of people as well as to enable continuation of the organization\'s activities in Brazil, especially in the most repressive dictatorship. Much more than a minor adjustment, as is supposed, these women formed a slight force, which gave the clandestine militants stability to continue the fight.
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Perez, Ricardo Perez. "TRAJETÓRIA INTELECTUAL DE CARLOS MARIGHELLA: DO PCB À ALN." Pontifícia Universidade Católica de Goiás, 2017. http://tede2.pucgoias.edu.br:8080/handle/tede/3635.
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The present study is based on an analysis of the intellectual trajectory of Carlos Marighella. Consequently, the construction and ideological line adopted by the ALN, one of the most important guerrilla organizations formed in Brazil after the 1964 civilmilitary coup. Therefore, the established sieve essentially included the writings of Carlos Marighella, founder and leader of the aforementioned revolutionary organization. The incendiary combined the dynamism of practical revolutionary with an intense literary production. Marighella's writings merge with the nature of the leftist guerrilla organization - the ALN - in which the whole ideological and doctrinal structure is initiated, including "organizational principles," "tactical principles," and "strategic principles." Then, it is possible to highlight, in the process of maturity of its texts, the theoretical, ideological and practical construction proposed by Marighella for the ALN that will converge in the action as guiding principle of the organization, bringing to the surface the sui generis contribution of its ideas to the Revolutionary left. The period comprised by the research began in 1948 when party teaching debates initiated due illegality that the Brazilian Communist Party had initiated and ended in 1969 with the assassination of Carlos Marighella for military repression.
O presente trabalho debruça-se numa análise sobre a trajetória intelectual de Carlos Marighella. Ilumina-se, consequentemente, a construção e linha ideológica adotada pela ALN, uma das mais importantes organizações guerrilheiras formadas no Brasil após o golpe civil-militar de 1964. Para tanto, o crivo estabelecido, essencialmente, abarcou os escritos de Carlos Marighella, fundador e líder da organização revolucionária citada. O guerrilheiro conjugou o dinamismo de revolucionário prático a uma produção literária intensa. Os escritos de Marighella fundem-se à natureza da organização guerrilheira de esquerda – a ALN –, neles, toda a estrutura ideológica e doutrinária é lançada, incluindo os ―princípios organizativos‖, os ―princípios táticos‖ e os ―princípios estratégicos‖. Com isso, é possível evidenciar, no processo de maturidade de seus textos, a construção teórica, ideológica e prática proposta por Marighella para a ALN que convergirá na ação como princípio norteador da organização, trazendo à superfície a contribuição sui generis de suas ideias para a esquerda revolucionária brasileira. O período abrangido pela pesquisa inicia-se em 1948 quando dos debates de direcionamento partidário inaugurados devido à ilegalidade que o Partido Comunista Brasileiro fora lançado e finaliza-se em 1969 com o assassinato de Carlos Marighella pela repressão militar.
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MAKUNTUALA, KEVA. "Desenvolvimento de compositos refratarios SiC-AlN e SiC-SiAlON." reponame:Repositório Institucional do IPEN, 2000. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9274.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Auzelle, Thomas. "Nanofils de GaN/AlN : nucléation, polarité et hétérostructures quantiques." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAY057/document.
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Usant de certaines conditions, la croissance épitaxiale de GaN sur un large panel de substrats donne lieu à une assemblée de nanofils. Cette géométrie filaire peut permettre la croissance d'hétérostructures libres de tous défauts cristallins étendus, ce qui les rendent attractives pour créer des dispositifs de hautes performances. En premier lieu, mon travail de thèse a visé à clarifier le mécanisme de nucléation auto-organisé des nanofils de GaN sur substrat de silicium. Dans ce but, une étude approfondie de la couche tampon d'AlN, déposée préalablement à la nucléation des nanofils, a été réalisée, mettant en évidence une inattendue forte réactivité de l'Al avec le substrat. La nécessité de la polarité azote pour la croissance des nanofils de GaN a été mise en lumière, bien que des nanofils contenant dans leur cœur un domaine de polarité Ga ont également été observés. Dans ces nanofils, une paroi d'inversion de domaine est présente et a été démontrée être optiquement active, exhibant une photoluminescence à 3.45 eV. Ensuite des hétérostuctures filaires GaN/AlN ont été synthétisée pour des caractérisations structurales et optiques. Il a été montré que le mode de croissance de l'hétérostructure peut être changé en fonction du diamètre du nanofil. En dernier lieu, en prenant avantage de la géométrie cylindrique des nanofils, des mesures de diffusion de porteurs de charge ont été réalisées dans des nanofils de GaN et d'AlNUsing specific conditions, GaN can be epitaxially grown on a large variety of substrates as a nanowire (NW) array. This geometry allows the subsequent growth of wire-like heterostructures likely free of extended defects, which makes them promising for increasing device controllability and performance. First, my PhD work has been devoted to the understanding of self-organized nucleation of GaN NWs on silicon substrates. For this purpose, a deep characterization of the growth mechanism of the AlN buffer deposited prior to NW nucleation has been done, emphasizing an unexpected large reactivity of Al with the substrate. The requirement of the N polarity to nucleate GaN NWs has been evidenced, although the possible existence of NWs hosting a Ga polar core has been observed as well. In these NWs, an inversion domain boundary is present and has been demonstrated to be optically active, having a photoluminescence signature at 3.45 eV. Next, GaN/AlN wire heterostructures have been grown for structural and optical characterization. It has been shown that by changing the wire diameter, different growth mode for the heterostructure could be reached.At last, thanks to the cylindrical geometry of NWs, the measurement of diffusion length for charge carriers in GaN and AlN NWs have been performed
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TABARY, PATRICK. "Etude du diagramme de phases al#2o#3-aln." Paris 11, 1997. http://www.theses.fr/1997PA112219.
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Cette etude du diagramme al#2o#3-aln pour des compositions moyennes comprises entre 0 et 50%mol aln a ete realisee par plusieurs techniques incluant le dosage par microsonde de castaing, la microscopie electronique en transmission, la diffraction des neutrons et l'analyse thermique differentielle a haute temperature. Les principaux elements du nouveau diagramme sont les temperatures de fusion des phases spinelles (entre 2045 et 2085c), la composition du point eutectique 12h+liquide+gamma-alon (40%mol aln) et le domaine de stabilite en composition de la phase phi'-alon au voisinage de la fusion (de 10 a 20%mol aln). Les temperatures d'equilibre des polytypes 21r, 12h et 27r ont ete reevaluees et une nouvelle phase du systeme quaternaire al#2o#3-aln-al#4c#3 a ete decrite. A l'aide de la met, de la diffraction des r. X et des neutrons nous avons determine les mailles, la position des lacunes et les maclages des phases modulees phi' et delta-alon, et confirme l'existence de domaines d'antiphase. La modelisation thermodynamique du diagramme a l'aide du programme thermocalc a ete realisee apres description des sous-reseaux des phases phi' et delta-alon et en introduisant les enthalpies de fusion des phases spinelles obtenues par atd. L'evaluation des contraintes residuelles dans le materiau a montre l'influence de la relaxation plastique au cours du refroidissement. Le procede industriel de nitruration de l'aluminium en presence d'alumine a ete reproduit en laboratoire et a une echelle semi-industrielle. Les temperatures d'initiation de la reaction, les temperatures maximales atteintes et les taux de nitruration ont ainsi pu etre determines.
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Kazan, Michel. "Spectroscopies vibrationnelles de AlN et des alliages AlxGa1-xN." Montpellier 2, 2006. http://www.theses.fr/2006MON20044.
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Koltsov, Alexey. "Physico-chimie du brasage de AlN : mouillage et réactivité." Grenoble INPG, 2005. http://www.theses.fr/2005INPG0174.
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Dans ce travail nous avons étudié les aspects physico-chimiques d'assemblage par brasage de composites céramique/céramique CMC(SiC) avec des pièces métalliques base Ni ou Co visant une température de fonctionnement de BOO. C. Ce type d'assemblage nécessite l'utilisation de matériaux intercalaires entre les deux pièces à braser, du fait de leur incompatibilité chimique et mécanique. Nous avons défini deux alliages de brasure permettant d'assembler d'une part le composite CMC(SiC) avec un matériau intercalaire céramique AIN (alliage Pr-Si) et, d'autre part l'intercalaire cèramique AIN avec une pièce mètallique (alliage base Ni contenant du Si et du Ti). L'étude de couplages entre mouillage, réactivité interfaciale et processus diffusionnels a permis d'élucider les mécanismes physico chimiques mis en jeu lors des interactions alliage liquides/substrats et d'optimiser la composition des alliages de brasure retenusLn this work we have studied the physicochemical aspects of the assembly by brazing of ceramic/ceramic composites CMC(SiC) with metallic pieces based on Ni or Co for applications at temperature of about BOO. C. This type of assembly requires the use of interlayer materials between the two solids to be brazed, because of their chemical and mechanical incompatibilities. We have developed two brazing alloys allowing to assembly on the one hand the composite CMC(SiC) with an AIN ceramic interlayer (Pr-Si alloy) and, on the other hand the AIN ceramic interlayer with a metallic piece (Ni based alloy containing Si and Ti). The study of couplings between wetting, interfacial reactivity and diffusion processes has allowed to clarify the physicochemical mechanisms taking place during liquide alloys/substrates interactions as weil as to optimize the compositions of the selected brazing alloys
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Gerges, Tony. "Préparation et étude de nanostructures 1D de nitrure d'aluminium fabriquées par électrofilage." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10319/document.
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Les nanostructures 1D d'AlN promettent des nouvelles applications dans la technologie des semi-conducteurs, des antennes optiques et des résonateurs nanomécaniques. Elles peuvent également aboutir à l'évolution de nouveaux composants d'instrumentation. Cette étude explore deux voies originales pour élaborer des nanofilaments d'AlN en procédant à la mise en forme par électrofilage couplée à un procédé d'élaboration de céramique. Deux stratégies d'élaboration peuvent être considérées selon que le système initial contient de l'oxygène ou non. La maîtrise des conditions de mise en forme (paramètres d'électrofilage) ainsi que l'optimisation des solutions utilisées (teneur en polymère et en précurseur) et des traitements thermiques, ont permis d'obtenir des filaments de taille submicronique (entre 100 nm et 400 nm), ainsi que des tubes d'une grande pureté chimique et stables sous air jusqu'à 550°C. Il est démontré que la qualité des nano-objets d'AlN dépend de leur méthode de fabrication. L'étude basée sur deux méthodes de fabrication, l'une sous air et l'autre sous atmosphère contrôlée, permet de présenter les avantages et les inconvénients de chacune de ces deux approches, la première étant dite « low-cost » par rapport à la secondeOne-dimensional (1D) AlN nanostructures promise the achievement of new applications in semiconductor technology, optical antennas and nanomechanical resonators. They can also lead to the development of new components for instrumentation. This study explores two original methods to elaborate AlN nanofilaments performing shaping by electrospinning, coupled to a process for producing ceramic. Two strategies can be developed depending on whether the initial system contains oxygen or not. The control of the conditions of shaping (electrospinning parameters) and the optimization of the used solutions (polymer content and precursor) and heat treatments, allowed the obtainment of submicron sized filaments (between 100 nm and 400 nm), as well as tubes with a high chemical purity, and stable in air up to 550 °C. It is demonstrated that the quality of the AlN nano-objects depends on their method of elaboration. The study of the two used methods, one in air and the other under controlled atmosphere, can show the advantages and disadvantages of each of these two approaches, the first being "low-cost" comparing to the second
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Abergel, Julie. "Matériaux piézoélectriques à forte déformation pour l'actionnement microsystème." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT030/document.
Full textAbstract:
Les actionneurs piézoélectriques se distinguent par leurs faibles temps de réponse et leurs rapports déflexion/ tension d’actionnement élevés. Dans ces travaux, nous nous attacherons à optimiser la déformation de matériaux piézoélectriques. La première approche consiste à augmenter le champ dans la couche active et la seconde à optimiser les coefficients piézoélectriques du matériau. Pour répondre à des problématiques d’actionnement basse tension, des couches de nitrure d’aluminium (AlN) ultraminces ont été déposées et caractérisées. Le coefficient e31,eff s’est avéré être constant entre 800 et 50 nm d’épaisseur, à une valeur de -0,8 C/m², ce qui est proche de l’état de l’art. Le caractère piézoélectrique de l’AlN à une épaisseur de 12 nm a été mis en évidence. Toujours dans l’optique de travailler à champ électrique élevé, une étude visant à augmenter le champ de claquage du titano-zirconate de plomb (PZT) par insertion d’atomes de lanthane a été menée. Le champ de claquage est amélioré de 35% environ, sans que la permittivité diélectrique et les coefficients piézoélectriques ne soit dégradés. La seconde approche consiste à optimiser les coefficients piézoélectriques. Pour cela, le Titano Zircoate de Plomb a été étudié au voisinage de différentes transitions de phases. La transition morphotropique est particulièrement favorable au niveau piézoélectrique, avec un coefficient e31,eff qui atteint -18 C/m² hors champ et -27 C/m² sous champ. La problématique de blocage de parois de domaines a été abordée. La transition de Curie se manifeste principalement au niveau diélectrique, avec une permittivité relative qui atteint 2640 à 370°C, soit près du double de la valeur mesurée à température ambiante. Les pertes diélectriques diminuent entre 25°C et 280°C, pour atteindre 1,6 %. Afin de bénéficier d’une transition critique, du PZT fortement dopé au lanthane a été déposé.Un comportement relaxeur a été mis en évidence et un coefficient piézoélectrique induit d31 de -25 pm/V a été mesuré. Les matériaux développés dans cette thèse ouvrent des perspectives pour la réalisation de microactionneurs et notamment de têtes d’imprimantes jet d’encrePiezoelectric actuators exhibit low response times and high deflection/actuation voltage ratios. This PhD thesis aims at optimizing their strain values by increasing the applied field and the piezoelectric coefficients. To target low voltage issues, Aluminum Nitride (AlN) ultrathin layers were deposited and characterized. e31,eff coefficient was found to be constant between 800 and 50 nm, at a value as high as -0.8 C/m². Piezoelectric behaviour was also shown for 12 nm-thick AlN layers, by three different ways. Still in order to apply high electric fields, a study was carried out to improve Lead Zirconate Titanate (PZT) breakdown field, by inserting lanthanum atoms. Breakdown field was improved by approximately 35%, with no decrease of permittivity or piezoelectric coefficients. Another optimization approach consists in increasing the material’s piezoelectric coefficients. In this view, PZT was characterized around several phase transitions. Near morphotropic phase boundary, piezoelectric effect was found to be enhanced: e31,eff coefficient raises up to -18 C/m² at low field conditions and -27 C/m² in actuating conditions. Domain wall pining issue was also discussed. Near Curie transition, dielectric properties were found to be enhanced, with a dielectric constant rising up to 2640 at 370C, which is almost twice as high as room temperature value. Furthermore, dielectric loss decreases from 25C to 280C to reach 1.6%. To profit from a critic phase transition, highly Lanthanum doped PZT was deposited. Relaxor behaviour was shown and an induced piezoelectric coefficient d31 of -25 pm/V was measured. Materials developed in this PhD thesis can be used to realize microactuators and especially inkjet printheads
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Yang, S. Y., and 楊勝裕. "Deposition and Characteristic of AlN/VN and AlN/ZrN Nanonaminates." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/58602109904062376219.
Full textAbstract:
碩士國立東華大學
材料科學與工程研究所
88
This project studies the microstructure and properties of AlN/VN and AlN/ZrN nanolamiate coatings. Advanced ion-assisted, high-rate, reactive and pulse-dc magnetron sputtering technique was used to deposit the nitride coatings on Si wafer and stainless steel substrates. The individual AlN layer, of which stable form is hexagonal wurtzite structure, can be stabilized into a cubic NaCl-form in AlN/VN multilayers when the AlN layer is below a critical thickness.It as found that under a critical thickness about 2.1 nm for the AlN layer, the AlN/VN multilayers exhibit a highly [111] textured superlattice structure., and an enhancement in film hardness which was up to 36 ~ 40 GPa under a given substrate bias of -125 V. Increasing or decreasing the substrate bias will affect film texture and hardness.XRD and TEM studies indicate that in the AlN/VN highly [111] textured superlattice structure, AlN layers have transformed into a metastable cubic NaCl-form from its normal hexagonal phase. However, in the case of AlN/ZrN coatings in our study, no highly textured superlattice structure, no cubic AlN phase and no hardness enhancement was observed.The results indicate that the lattice structure and lattice match in AlN-containing nanolaminates are important for formation of metastable c-AlN phase and highly-textured superlattice structures.
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Hsiao, Kuo I., and 蕭國益. "Deposition and Properties of AlN/TiN & AlN/ZrN Superlattice Coatings." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/2vg9y7.
Full textAbstract:
碩士國立東華大學
材料科學與工程學系
87
This project studies the preparation and properties of a new class of advanced multilayered AlN/TiN and AlN/ZrN coatings. It investigates the relationships among processing methods and the coating microstructure and properties and facilitates the understanding of property enhancement observed in the coatings. Advanced ion-assisted, high-rate, reactive dc and pulse dc magnetron sputtering technique combined with several innovative methods and processing strategies is used to deposit the nitride coatings. AlN exhibits polymorphism depending growth conditions. The most stable form under standard condition is hexagonal wurtzite structure. Multilayer coatings of AlN/TiN and AlN/ZrN have been deposited onto various substrates such as silicon (111) or (100) wafer and glass slide and stainless steel simultaneoususly using a dual-cathode reactive unbalanced dc magnetron sputtering system. AlN/TiN coatings are prepared by sputtering from Al and Ti targets , AlN/ZrN sputtering from Zr and Al targets in side-by-side configuration in Ar + N2 atmosphere, onto various substrates fixed on a rotating substrate holder. The rotation of the substrate holder varied from 0.1 to 16 r.p.m. corresponding to a unit bilayer thickness (Λ) of 1-10 nm. The total film thickness of AlN/TiN and AlN/ZrN were about 1~2 μm. Structural characterization were performed by measure of X-ray diffraction. The Vickers microhardness in the load 25 g was measured. Depending on the unit bilayer thickness and substrate bias, hardness valves of 1000-3300 kgf/mm2 were obtained at the bulk (thin film + substrate). It was found that under a critical thickness about ~2.2nm for the AlN layer the AlN/TiN nanolaminates exhibit a highly textured [111] orientation superlattice structure and an enhancement in film hardness up to 3300 kgf/mm2. X-ray diffraction indicate that in the highly textured [111] orientation AlN/TiN multilayers, AlN has transformed into a nano-stabilized cubic form from the normal hexagonal phase. XRD patterns indicate AlN/TiN superlattice structure not only is affected by on the unit bilayer thickness but also substrate bias. However, in the case of AlN/ZrN multilayers, no stabilization of cubic AlN was observed under the growth conditions comparable to those for AlN/TiN multilayers. The effect of stress and lattice mismatch on the hexagonal-to-cubic transformation is discussed.
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Hsiao, Gwo-Yih, and 蕭國益. "Deposition and Properties of AlN/TiN & AlN/ZrN Superlattice Coatings." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/24045468298732152343.
Full textAbstract:
碩士國立東華大學
材料科學與工程研究所
87
This project studies the preparation and properties of a new class of advanced multilayered AlN/TiN and AlN/ZrN coatings. It investigates the relationships among processing methods and the coating microstructure and properties and facilitates the understanding of property enhancement observed in the coatings. Advanced ion-assisted, high-rate, reactive dc and pulse dc magnetron sputtering technique combined with several innovative methods and processing strategies is used to deposit the nitride coatings. AlN exhibits polymorphism depending growth conditions. The most stable form under standard condition is hexagonal wurtzite structure. Multilayer coatings of AlN/TiN and AlN/ZrN have been deposited onto various substrates such as silicon (111) or (100) wafer and glass slide and stainless steel simultaneoususly using a dual-cathode reactive unbalanced dc magnetron sputtering system. AlN/TiN coatings are prepared by sputtering from Al and Ti targets , AlN/ZrN sputtering from Zr and Al targets in side-by-side configuration in Ar + N2 atmosphere, onto various substrates fixed on a rotating substrate holder. The rotation of the substrate holder varied from 0.1 to 16 r.p.m. corresponding to a unit bilayer thickness (Λ) of 1-10 nm. The total film thickness of AlN/TiN and AlN/ZrN were about 1~2 μm. Structural characterization were performed by measure of X-ray diffraction. The Vickers microhardness in the load 25 g was measured. Depending on the unit bilayer thickness and substrate bias, hardness valves of 1000-3300 kgf/mm2 were obtained at the bulk (thin film + substrate). It was found that under a critical thickness about ~2.2nm for the AlN layer the AlN/TiN nanolaminates exhibit a highly textured [111] orientation superlattice structure and an enhancement in film hardness up to 3300 kgf/mm2. X-ray diffraction indicate that in the highly textured [111] orientation AlN/TiN multilayers, AlN has transformed into a nano-stabilized cubic form from the normal hexagonal phase. XRD patterns indicate AlN/TiN superlattice structure not only is affected by on the unit bilayer thickness but also substrate bias. However, in the case of AlN/ZrN multilayers, no stabilization of cubic AlN was observed under the growth conditions comparable to those for AlN/TiN multilayers. The effect of stress and lattice mismatch on the hexagonal-to-cubic transformation is discussed.
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Wu, Yu-Hao, and 吳育豪. "Combustion Synthesis of AlN." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/x5k4ur.
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Chiu, Hung-Jen, and 邱黌壬. "Investigating Characteristics of AlN-ZnO/ZnO/AlN-ZnO Structure Applied to Multi-Quantum Well." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/3wks3w.
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碩士國立虎尾科技大學
光電與材料科技研究所
103
In this study, by using RF magnetron co-sputtering system with ZnO and AlN target, respectively, deposited un-doped ZnO thin films and ZnO doped Al thin film, and using AlN-ZnO sputtering thin film to be a barrier layer, un-doped ZnO thin films to be active layers to produce double heterostructures and multi-quantum well structure, second annealing under vacuum ambient activates the dopant atoms in the films. After annealing under vacuum ambient, We measured our samples about the electrical properties, optical properties of thin films with photoluminescence light-emitting properties and the composition with the film crystal structure and analysis the thin film carrier mechanism and conduction type. Result of the study, after annealing under vacuum ambient, observed the average transmittance were over 80% about the double heterostructure (AlN-ZnO/ZnO/AlN-ZnO) and multi quantum well structure, due to the interface of AlN-ZnO / ZnO diffusion of aluminum atoms substituted the zinc atom, to support more electronic carrier, therefore, comparing with the un-doped ZnO, the electron carrier concentration has improved significantly of the double heterostructure and Multi-Quantum Well structure. Next, the barrier layer(AlN-ZnO) and un-doped well layer(ZnO) repeat stacked to form a multi-quantum well structure, observed the multilayer structure can provide more potential energy well, so the more electrons and holes are confined to potential energy wells layer, leading to the peak intensity increases of the radiative recombination radiation with increasing the number of quantum wells and has significantly enhanced the phenomenon, when quantum well layer increased to thirty period, due to quantum well stacked a lots, the number of electron and hole composite reach a saturation, due to the structure with multilayer stack makes a lot of accumulated stress, caused by the crystallization characteristics worse, Which led to a multi-quantum well structure luminous intensity rise less obvious, even the multiple-quantum well’s period were more than 25-period, the luminous intensity will gradually shows the trend of a level of saturation trend.
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Hsieh, Cong-Han, and 謝琮瀚. "Microwave Sintering of AlN Ceramics." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/w3nrgk.
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碩士國立成功大學
化學工程學系碩博士班
92
High thermal conductivity, good electrical insulation, low dielectric constant, and low thermal expansion coefficient make aluminum nitride a very promising ceramic material for electronic substrate applications. However, the high cost of this material lead it to popularization hardly. The single-mode microwave furnace was used to sinter high thermal conductivity AlN ceramics. For the combustion synthesized AlN product and the advantages of microwave sintering the fast heating and saving of energy we can get the cheaper synthesize and applications. First, the synthesized AlN product was milled to desired sizes by using an attritor with ZrO2 balls. The powder was mixed with additives and binder. Then, made to green bodies, and microwave sintering. Last, we studied the density, thermal conductivity, grain, and microstructure with the sintered body. In the study, we found that using Y2O3 as the additive for sintering, 5wt% of the amount of Y2O3 sintering in 1900℃for 30 minutes can get the best shrin- kage (18.07%), density (3.30g/cm3) and thermal conductivity (153.38W/m-K). However using the Y2O3-Li2CO3 complex additive, it can get the higher density and better thermal conductivity (ρ=3.15 g/cm3, k=112.97 W/m- K) then only using Y2O3 additive(ρ=2.80 g/cm3, k=80.20 W/m- K). As sintering for 120 minutes with the Y2O3-Li2CO3 complex additive, we can gain the density, 3.21 g/cm3 and, an especially high thermal conductivity, 156.79W/m-K. Sintering with small particles size with complex additive, we can get the high density (3.33 g/cm3), but the high concentration of oxygen caused the low thermal conductivity for sintering body.
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Jian, Guangdui, and 簡光兌. "Theoretical Investigation Of SAW Propagation Characteristics In AlN/ZnO/Silicon And ZnO/AlN/Silicon Structures." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/49803175650391733584.
Full textAbstract:
碩士義守大學
電機工程學系
100
In this thesis, the finite element method is employed to calculate surface acoustic wave (SAW) characteristics in (100)ZnO/Silicon based structures with different electrical interfaces; i.e., IDT/(100)ZnO/Silicon, (100)ZnO/IDT/Silicon, IDT/(100) ZnO/thin metal film/Silicon, and thin meta film/(100)ZnO/IDT/Silicon. The effects of Al electrodes on phase velocity, coupling coefficient, and reflectivity of SAWs are illust rated. Propagation characteristics of SAWs in (002)ZnO/Silicon and (100)AlN/Silicon and (002)AlN /Silicon structures are also presented for comparison. Propagation characteristics of SAWs in three-layer structures such as (100)AlN/ (100)ZnO/Silicon, (002)AlN/(002)ZnO/Silicon, (100)ZnO/(100)AlN/Silicon, (002) ZnO/(002)AlN/Silicon are also studied and presented.
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詹凱評. "Study of the residual stress and wear resistance in the AlN/VN and AlN/TiN multilayers." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/68004024071379946436.
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碩士國立東華大學
材料科學與工程研究所
89
Abstract The residual stresses and wear resistance of the AlN/VN and AlN/TiN multilayers, are pursured in this studies. The AlN/VN and AlN/TiN multilayers with critical thickness about 2.1nm and 1.6nm, respectively in AlN layer, The exhibit a highly [111] textured superlattice structure, and an enhancement in film hardness which was up to 36GPa and 34GPa. The residual stresses for all the films prepared in this study were all compressive with the values from 5 to 1400 MPa. The films with higher hardness have higher stresses, and an highest residual stresses was 1.4GPa in the film with superlattice. The film stresses increase with increasing film period thickness in addition to the film with superlattice. It is important to lengthen the lift of machine and avoid missing the precision of machine under high-speed and long-time usage. In this study, we hope to improve the wear resistance of the films by deposition technology. The AlN/VN and AlN/TiN multilayes would improve apparently the wear resistance of the substrates, as tool steel (SKH2) and stainless steel (S.S.304) in this study. The multilayes with thinners period thickness (higher rotating rate) have smaller friction coefficient and wear volume, indicating good wear resistance. On the other hard, The multilayers with the existance of superlattice structure have the greatest hardness, however, they have the highest friction coefficient and wear volume, which indicate poor wear resistance. The samples with the greater hardness were found to have higher stress. It is easier to crack and produce wear debris in the samples with higher stress during wear-test procedure. The mass-produced wear debris with greater hardness would destroy the films further, which induce higher friction coefficient. Therefore, it is not adequate to use the hardness as the measurement of wear resistance. In addition, the effect of the substrate on the wear resistance is little in this study.
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Chou, Chun Yu, and 周仲瑀. "Preparation of AlN Composites by Infiltration." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/12902749294110674620.
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碩士國立臺灣大學
材料科學與工程學研究所
98
The infiltration of copper into AlN powder compact is investigated in the present study. The oxide/sulfide interphase is introduced into both AlN green body and copper matrix with the help of co-existed calcium sulphate. The interphase and inclusions are determined by using XRD technique; the composition by EPMA analysis. The possible role of yttrium in the system is evaluated by using a model system composing of 50% Y2O3 and 50% AlN. The possible interphases are Cu2S, Cu1.8S or other copper-sulfide compounds. The reaction phases, copper alumina oxide and copper alumina sulfide are also observed. By increasing the infiltration temperature, more reaction phases are formed at the interphase between AlN and copper. The gas produced by firing calcium sulfate is different in various atmospheres. More oxygen is formed by firing calcium sulfate in an atmosphere composing of 5%H2/95%N2. On the other hand, less sulfur (or sulfur dioxide) is generated by firing calcium sulfate in 5%H2/95%N2. The distribution of oxygen and sulfur is uniform as the 5%H2/95%N2 atmosphere is used. The thermal conductivity of the infiltrated specimens is lower than the theoretical predictions due to their low density. Nevertheless, the thermal conductivity values are close to the theoretical values by assuming that the specimens are fully dense. This may imply that the thermal resistance of interphases is low.
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Ye, Guo-Liang, and 葉國良. "Tribological properties of TiN/AlN multilayers." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/66623814839431092706.
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碩士國立成功大學
機械工程學系碩博士班
91
The main purpose of this study is to research the tribological properties、oxidation ability and the sputtering parameters to be a super-lattice structure of the TiN/AlN multilayers . The TiN/AlN multilayers prepared by a mixed sputtering system(medium frequency twin magnetron sputtering system and unbalanced magnetron sputtering system). The study has two stages : the first stage, to change the nitrogen flow rate, and to probe into the influence of mechanical properties and element component of the TiN/AlN multilayers ; the second stage , to change the rotational speed of the holder , the purpose is makes the period of the TiN/AlN multilayers less than 3nm , and to be formed a super-lattice TiN/AlN multilayers. The research of the first stage , we know that the hardness of the TiN/AlN multilayers increase with the nitrogen content , as well as the adhesion of the TiN/AlN multilayers . after the wear test , we found the best wear resistance of the TiN/AlN multilayers is the specimen N20(nitrogen flow rate is 20 sccm). By the XRD analysis , we know that the TiN/AlN multilayers can be formed super-lattice structure that rotational speed of the holder is 4rpm and 5rpm. Through the wear test , wear resistance of the super-lattice TiN/AlN multilayers is more excellent than others non-superlattice TiN/AlN multilayers . In the oxidation test, the super-lattice TiN/AlN multilayers(specimen R4) improved oxidation resistance ability 16 times more than TiN coatings . In the turning and drilling tests , the tool life of coating a super-lattice TiN/AlN multilayers on cutting tools are more longer than others conditional tools. To confirm from above tests , in high temperature status , the super-lattice TiN/AlN multilayers really be able to improve the tool life.
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Chiu, Chi-Kuang, and 邱繼廣. "AlN capping layer for ion implantation." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/98591244598944506827.
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碩士國立中央大學
物理研究所
91
In this thesis, we deposited an AlN capping layer on GaN to prevent the decomposition of GaN surface. GaN films were grown by MOCVD at about 1050℃. In the thermal annealing process after ion implantation, the temperature higher than 1050℃ will cause the decomposition of GaN surface. By using the Hall measurement, we compared the electrical properties of GaN with AlN capping layer and without capping after thermal annealing. The 28Si+ implantation into p-type GaN followed by thermal annealing will makes the electrical properties transform from p-type to n-type. In the Hall measurement results, the GaN without capping has carrier concentration about 3.73x1013 cm-2, and the GaN with capping layer has carrier concentration about 1.02x1014 cm-2. Activation efficiency was improved from 3.7% to 10%. If the GaN substrates were heated during deposition process, then the adhesion of AlN films on GaN will be better to get improvement for protection on GaN surface.
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高璿皓. "High Current Density InN/AlN MISHFETs." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/73179294710788303005.
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碩士國立清華大學
工程與系統科學系
95
Abstract InN/AlN metal-insulator-semiconductor heterojunction field-effect transistors with a gate-modulated drain current and a clear pinch-off characteristic have been demonstrated. The devices were fabricated using high-quality InN (26 nm)/AlN (100 nm) epifilms grown by plasma-assisted molecular-beam epitaxy on Si (111) substrates. The devices exhibited a current density higher than ~530 mA/mm with a 5-�慆 gate length. The pinch-off voltage was at ~ –7 V with an associated drain leakage current less than 10 �嫀/mm. The observed high current density may be attributed to the high sheet carrier density due to the large spontaneous polarization difference between InN and AlN.
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Huang, Xiaogeng, and 黃孝耕. "Theoretical Analysis Of Surface Acoustic Waves Propagation Characteristics Using ZnO /AlN /Diamond And AlN / ZnO /Diamond Structures." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/95932853757982808034.
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碩士義守大學
電機工程學系
100
This thesis, the finite element method analysis software Comsol Multiphysics are employed to evaluate propagation characteristics of surface acoustic waves devices (SAW)in piezoelectric composite structures of Diamond, AlN and ZnO. In this study , SAW characteristics in (100)ZnO/(100)AlN/Diamond, (002)ZnO/(002)AlN/Diamond, (100)AlN /(100)ZnO/Diamond, and (002)AlN/(002)ZnO/Diamond, such as phase velocity, coupling coefficient, and temperature coefficient of delay for the second mode are analyzed. These coupling-of-mode parameters uses Matlab software to draw Contour maps are presented versus the thickness of the piezoelectric films. The best piezoelectric composite structure is then be used to analyse the effects of the Aluminum electrodes on SAW propagation characteristics.
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Chang, Jen-Hao, and 張仁豪. "A Study on the Characteristics of AlN-ZnO/ZnO/AlN-ZnO Double Heterojunction and Quantum Wells Structure." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/7x6796.
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碩士國立虎尾科技大學
光電與材料科技研究所
102
In this study, the use of RF magnetron sputtering system, namely the use of zinc oxide, aluminum nitride target, AlN-ZnO cosputtered films as a barrier layer and an undoped ZnO film as a active layer to production double heterojunction and quantum well structure. Measurement optical and electrical properties of the structure, Optical characteristic, PL characteristic and crystallize,by changing the thickness of the different active layer .The results,AlN-ZnO/ZnO/AlN-ZnO double heterojunction and quantum well structure after vacuum annealing, the average penetration can be more than 80%. The AlN-ZnO/ZnO interface of the diffusion of aluminum atoms substituted with a zinc atom, the electron carrier to provide more,therefore, compared with the non-doped zinc oxide, double heterostructures and quantum well structure electron carrier concentration has improved significantly. With the well thickness reduction,the barrier layer of aluminum atoms diffuse the situation more obvious,thus the radiative recombination centers gradually weakened and towards long-wavelength red shift. Further short-wavelength photoluminescence spectrum fitting analysis can be found when the well region thickness is reduced from 50 nm to 7 nm, the peak fitting band edge radiation in the blue-shift of about 35 meV, mainly because with the well layer thickness decreases, the quantum confinement effect will be more obvious, therefore, to produce a blue shift and blue shift size similar results with the theoretical values calculated. Then,the AlN-ZnO barrier layer and undoped ZnO well layer are repeatedly stacked to form multiple quantum well structure. It can be found, the multilayer structure can provide more potential wells, so that more electrons and holes are confined potential well zones, increasing the number of electrons and holes complex, leading to radiative recombination radiation peak intensity with quantum wells periods to increase of phenomena which have significantly enhanced. The radiative recombination radiation peak positions with increasing of quantum wells periods have blue shift and then redshift phenomenon, mainly because with increasing of quantum wells periods, quantum effects are more apparent when the periods of quantum wells increase to ten periods, due to excessive film stack, resulting in a large accumulation of stress in the structure, resulting in crystallization characteristics deteriorate, resulting redshift.
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Wang, Sheng-Chih, and 王勝志. "Electroreflectance spectra of AlGaN/AlN/GaN heterostructure." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/y284p4.
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碩士國立中山大學
物理學系研究所
96
Electroreflectance spectra of AlGaN/AlN/GaN heterostructures were measured at various biased voltages (Vdc). Strengths of the internal electric field in AlGaN (FAlGaN) were evaluated from periods of Franz-Keldysh oscillations (FKOs), which were observed above band-gap energy of AlGaN. The relation between FAlGaN and Vdc exhibits an anomalous behavior, which is different from the previous results of the AlGaN/GaN heterostructure. It agrees with the theoretical result of a Poisson-Schrödinger calculation, which shows that two dimensional electron gas (2DEG) exists not only in quantum well (QW) at AlN/GaN interface, but also in QW at AlGaN/AlN interface. This is also consistent with electron-density distribution obtained by capacitance-voltage measurements. When Vdc becomes more negative, the previous mechanism of depleting 2DEG is through flatting one side of QW. However, it was found that the depletion of 2DEG can also occur when the top of valence band at surface becoming higher than bottom at QW.
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Polster, Tobias Albrecht Arne. "AlN als piezoelektrisches Funktionsmaterial in der Mikrosystemtechnik /." 2006. http://www.gbv.de/dms/ilmenau/abs/520882792polst.txt.
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Tseng, Ching-Lun, and 曾慶綸. "Research of the AlN solar selective film." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/vdpmyh.
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碩士國立中央大學
光電科學與工程學系
104
In this thesis, colored solar selective absorbing films have been designed and fabricated. We use only one material, aluminum, for the sputtering deposition process, and fill different amounts of nitrogen to obtained variety multi-layer film of aluminum nitrogen. The refractive index and extinction coefficient depend on the content of nitride. We choose AlN-14%、AlN-18% as high and low refractive index material and adjusted the thickness of the outermost AlN-18% layer to contract the appearance of color. Then we measured the reflectance spectra of multi-layer film to calculate the absorption and emission. For calculating the absorption of the stacks including different thickness, we substituted spectral reflectance into equations. The result of absorbance is close to 90% and the emittance is less than 3%. The colors located on CIE chromaticity diagram is not much difference from actual samples. That indicates the color control is feasible.
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Ku, Kuo-Hsin, and 古國欣. "The growth of pentacene on hydrophobic AlN." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/13246440044034043237.
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Chen, Jen-Chang, and 陳政權. "The synthesis of AlN by SHS method." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/56342790251176351133.
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碩士國立成功大學
化學工程學系
89
Abstrate The AlN synthesized by shs method is very complex. This process including multiphase and reaction, leading to realize the mechanism detailedly is not easy. In order to develop the new process, it is necessarily to realize the mechanism at first. This work contains two parts. Part Ⅰ, the mechanism of shs method for AlN, Part Ⅱ, the morphology and crystal growth mechanism of AlN by shs method. At first, in views of macro energy balance to realize what factors influence the process. Secondly, in views of micro reaction and crystal growth to find the micro roles of this macro factors which influence the process. This result will not only facilitate to develop the shs process for AlN, but to initiate the new method to control the morphology of AlN.
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Yang, Yun-Da, and 楊昀達. "Preparation and Thermal Conductivity of Dense AlN." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/00070326956529050631.
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碩士國立成功大學
材料科學及工程學系碩博士班
92
In order to reduce the cost of alumina nitride substrate, it is essential to develop a low temperature sintering process of alumina nitride with high density and high thermal conductivity. According to the motivation mentioned above, Li2O,Y2O3, and CaO are used as additives in the liquid-phase sintering process which was fulfilled in 1600℃ to prepare the aluminum nitride with high density and thermal conductivity. The microstructure, thermal conductivity, and mechanical properties of the sintered alumina nitride were investigated. A sintered alumina nitride with more second phases (YAG and YAM) distributed in the grain boundaries was obtained by a process, which AlN powders containing 5wt% Y2O3-CaO (Y2O3/CaO=13/7) were sintered to 1650℃ with a rate of 6 /min then cooling down the temperature from 1650℃to 1550℃, holding for 4 hours , and finally reducing the temperature to room temperature with a rate of 6℃/min. A sintered bulk with 91.4% of calculated density was obtained using the same additives and raising the temperature from room temperature to 1600℃ with a rate of 6℃/min then holding for 2 hours. In the sintering condition of 1600℃ for 5 hours, the sintered body with 95.2% of calculated density was obtained, which showed the highest thermal conductivity of 165.8 W/mK and the largest grain size of 3.12μm in this study.
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Shia, Ho-Shin, and 謝何興. "Ag filler for brazing of AlN research." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/97189648691371567685.
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Ho, Wei-Lin, and 何韋霖. "Synthesis and Optical Properties of AlN nanowires." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/36027775180286174094.
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碩士中國文化大學
材料科學與奈米科技研究所
99
This study for the production of aluminum nitride nanowires, using some metal (nickel, gold) coated on sapphire by magnetron sputtering. Then we growth AlN nanowires using Chemical Vapor Deposition (CVD), and the substrate and aluminum (Al powder 99.97%) into the high-temperature furnace and ammonia (NH3) reaction by vapor - liquid - solid (VLS) mechanism, the sapphire substrate grown AlN nanowires, and modulation reaction time (15 minutes, 30 minutes, 60 minutes) and the reaction temperature (1100℃, 1200℃, 1300℃) to explore the aluminum nitride nanowire growth process. The morphology was analyzed by field emission scanning electron microscopy (FE-SEM),The size of the AlN nanowires are 50-150 nm in diameters and several μms in lengths.High resolution transmission electron microscopy (HR-TEM) and selection diffraction (SAED) patterns of AlN nanowires showed that it is single-crystalline structure.The structures and component were characterized by means of X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS).Using the photoluminescence spectrum (PL) analysis of the AlN nanowires optical properties. Keyword: AlN,nanowires, CVD, PL
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Chang, Te-Chyuan, and 張德全. "Study of growth and characteristic of AlN." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/jz6jcs.
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碩士國立臺北科技大學
光電與平面顯示器產業研發碩士專班
95
This dissertation investigates the growth and characteristics of Al oxide doped Indium oxide alloys on sapphire and AlN by RF reactive magnetron sputtering. Under optimizing the condition, to AlN growing on the nitrogen gallium base plate, there is a diffraction peak in X-ray diffraction pattern, and half it about 680 arcs second . By reflect spectrum can estimate their can the crack is nearly 6.08 eV. In addition, this thesis also studies the nitrogen aluminium with one ohm of characteristics of contacting of Al and ln separately. To the contact situation of AlN/ln, under the temperature of nitrogen environment and 600℃, the alloy is 10 minutes, can receive the minimumresistance value.
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Lin, En-Shuo, and 林恩碩. "Fabrication and Characterization of T-gate AlIn(Ga)N/AlN/GaN High Electron Mobility Transistors." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/d3r4s6.
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碩士國立中央大學
電機工程學系
107
Lattice matched Al0.83In0.17N/GaN high electron mobility transistors (HEMTs) have attracted a lot of interests as an alternative to the most matured AlGaN/GaN HEMTs for high power millimeter-wave devices because of its high density two dimensional electron gas (2DEG) at the heterointerface, even with sub-10 nm barrier. However, in spite of having such advantages over its AlGaN counterparts, it suffers from In segregation, compositional inhomogeneity and high off-state leakage current. AlInGaN/GaN HEMTs recently emerges as one of the promising candidate for mm-wave power applications. It is reported to have highest miscibility after AlGaN, among all the III-nitride materials. However, many of its properties and device performances are yet to be explored before its successful commercial deployments. This thesis aims at comparing the DC and RF performances of AlInN/GaN and AlInGaN/GaN HEMTs grown on 150 mm silicon (111) substrates. Devices fabricated with Lg= 0.4 µm/Lgd= 2 µm show off-state breakdown voltage of 81V and 57V with AlInGaN and AlInN barriers respectively. Furthermore, the AlInGaN/GaN and AlInN/GaN HEMTs with the same dimensions exhibit a current gain cut-off frequency (fT) of 35.3 GHz and 18 GHz and a power gain cut-off frequency (fmax) of 40.3 GHz and 24.5 GHz respectively. Extracted small signal parameters indicate, higher intrinsic transconductance (gmi) is one of the reasons for significantly higher fT/fmax in AlInGaN barrier HEMTs. Highly conductive T-gate with low input resistance and small footprint is desirable for devices operating at mm-wave frequency. However, it introduces additional gate parasitic capacitance, resulting lower fT. Therefore, highly optimized T-gates are needed to balance the fT/fmax ratio. A tri-layer photoresist of ZEP-A7/LOR/ZEP-A7 is developed to obtain high profile T-gates. The Idss increases from 522 mA/mm to 893 mA/mm, the transconductance increases from 287 mS/mm to 370 mS/mm and fT/fmax increase from 35.3/40.3 GHz to 83/95 GHz in AlInGaN HEMT by scalling down Lg from 0.4 µm to 0.16 µm. A reduction in parasitic gate capacitance and parasitic gate resistance from 21 ohm to 7 ohm may be attributed to the improved RF performances. This work further demonstrates that the AlInGaN/GaN HEMTs with highly optimized T-gates are excellent candidates for high power mm-wave applications. Furthermore, I consider substrate parasitic effect and remove substrate parasitic parameters by ADS simulation program. The extracted fmax is 103 GHz which indicated low resistivity silicon substrate will reduce high frequency result.
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Chen, Chih-Yao. "Simulation of Optical Properties ofGaN/AlN Quantum Dots." 2005. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2707200518183400.
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Weinberger, Stefan Albrecht Arne. "Piezoelektrische Funktionsstrukturen aus AlN für integrierte mikrotechnische Sensoren /." 2007. http://www.gbv.de/dms/ilmenau/abs/546595197weinb.txt.
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