{"id":55304,"date":"2023-02-03T15:24:06","date_gmt":"2023-02-03T13:24:06","guid":{"rendered":"https:\/\/www.iemn.fr\/?p=55304"},"modified":"2023-02-03T15:24:06","modified_gmt":"2023-02-03T13:24:06","slug":"these-kadi-t-contribution-au-developpement-dune-methode-a-ondes-acoustiques-de-surface-hautes-frequences-dediee-a-la-caracterisation-ultrasonore-des-structures-a-couches-minces-et-au-siliciu","status":"publish","type":"post","link":"https:\/\/www.iemn.fr\/en\/these\/these-2021\/these-kadi-t-contribution-au-developpement-dune-methode-a-ondes-acoustiques-de-surface-hautes-frequences-dediee-a-la-caracterisation-ultrasonore-des-structures-a-couches-minces-et-au-siliciu.html","title":{"rendered":"THESE KADI T- Contribution au d\u00e9veloppement d\u2019une m\u00e9thode \u00e0 ondes acoustiques de surface hautes fr\u00e9quences d\u00e9di\u00e9e \u00e0 la caract\u00e9risation ultrasonore des structures \u00e0 couches minces et au silicium m\u00e9soporeux"},"content":{"rendered":"<div 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class='container av-section-cont-open' ><div class='template-page content  av-content-small alpha units'><div class='post-entry post-entry-type-page post-entry-55304'><div class='entry-content-wrapper clearfix'>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-ldok2oju-2014868967c3ab00c8ef97957a76e52e\">\n#top .av-special-heading.av-ldok2oju-2014868967c3ab00c8ef97957a76e52e{\nmargin:0 0 10px 0;\npadding-bottom:4px;\n}\nbody .av-special-heading.av-ldok2oju-2014868967c3ab00c8ef97957a76e52e .av-special-heading-tag .heading-char{\nfont-size:25px;\n}\n.av-special-heading.av-ldok2oju-2014868967c3ab00c8ef97957a76e52e .av-subheading{\nfont-size:15px;\n}\n<\/style>\n<div  class='av-special-heading av-ldok2oju-2014868967c3ab00c8ef97957a76e52e av-special-heading-h2  avia-builder-el-1  el_after_av_layerslider  el_before_av_hr  avia-builder-el-first'><h2 class='av-special-heading-tag'  itemprop=\"headline\"  >THESE: KADI T- Contribution au d\u00e9veloppement d\u2019une m\u00e9thode \u00e0 ondes acoustiques de surface hautes fr\u00e9quences d\u00e9di\u00e9e \u00e0 la caract\u00e9risation ultrasonore des structures \u00e0 couches minces et au silicium m\u00e9soporeux <\/h2><div class=\"special-heading-border\"><div class=\"special-heading-inner-border\"><\/div><\/div><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-18u73nj-dad6a947580930e400fc42ba200e80f1\">\n#top .hr.av-18u73nj-dad6a947580930e400fc42ba200e80f1{\nmargin-top:5px;\nmargin-bottom:5px;\n}\n.hr.av-18u73nj-dad6a947580930e400fc42ba200e80f1 .hr-inner{\nwidth:100%;\n}\n<\/style>\n<div  class='hr av-18u73nj-dad6a947580930e400fc42ba200e80f1 hr-custom  avia-builder-el-2  el_after_av_heading  el_before_av_textblock  hr-left hr-icon-no'><span class='hr-inner inner-border-av-border-thin'><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n<section  class='av_textblock_section av-jriy64i8-2f4600354c0449b610997916bbd9b6bc'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" >\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-13ewzjw-68e036126b913e5028f77311dc66b825\">\n.av_font_icon.av-13ewzjw-68e036126b913e5028f77311dc66b825{\ncolor:#bfbfbf;\nborder-color:#bfbfbf;\n}\n.av_font_icon.av-13ewzjw-68e036126b913e5028f77311dc66b825 .av-icon-char{\nfont-size:60px;\nline-height:60px;\n}\n<\/style>\n<span  class='av_font_icon av-13ewzjw-68e036126b913e5028f77311dc66b825 avia_animate_when_visible av-icon-style- avia-icon-pos-left avia-icon-animate'><span class='av-icon-char' aria-hidden='true' data-av_icon='\ue8c9' data-av_iconfont='entypo-fontello' ><\/span><\/span>\n<p><strong>KADI T.<br \/>\n<\/strong><\/p>\n<p>Soutenance : <strong>15 Juin 2021<br \/>\n<\/strong>Th\u00e8se de doctorat en Acoustique, Universit\u00e9 Polytechnique Hauts de France<\/p>\n<p><a href=\"https:\/\/theoreme.uphf.fr\/notice\/view\/uvhc-ori-oai-wf-1-2911?menuKeyBack=theoreme&amp;submenuKeyBack=news&amp;resultBackUrl=&amp;lightbox=true\">https:\/\/theoreme.uphf.fr\/notice\/view\/uvhc-ori-oai-wf-1-2911?menuKeyBack=theoreme&amp;submenuKeyBack=news&amp;resultBackUrl=&amp;lightbox=true<\/a><\/p>\n<\/div><\/section>\n<section  class='av_textblock_section av-jtefqx33-628129dba2299b2ecd65ebfc92eac29d'   itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/BlogPosting\" itemprop=\"blogPost\" ><div class='avia_textblock'  itemprop=\"text\" ><div  class='hr av-kjh3zw-4dff888f744b728a1aca9b3a0971493a hr-default  avia-builder-el-6  avia-builder-el-no-sibling'><span class='hr-inner'><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n<ul>\n<li><\/li>\n<\/ul>\n<h5>Summary:<\/h5>\n<p>Ce travail rentre dans le cadre de la caract\u00e9risation des couches minces, de rev\u00eatements et de surfaces fonctionnelles (\u00e9paisseur, constantes \u00e9lastiques, porosit\u00e9?). Parmi les m\u00e9thodes de caract\u00e9risation potentielles, les m\u00e9thodes ultrasonores employant des ondes de surface (SAW) sont particuli\u00e8rement int\u00e9ressantes. En effet, les SAW de type Rayleigh se propagent \u00e0 la surface d\u2019un mat\u00e9riau et l\u2019\u00e9nergie v\u00e9hicul\u00e9e par ces ondes est confin\u00e9e sous la surface sur une profondeur de l\u2019ordre d\u2019une longueur d\u2019onde. Dans le cas de structures de type couche sur substrat, les SAW deviennent dispersives. En exploitant cette dispersion sur une large bande de fr\u00e9quences, des variations importantes de vitesses peuvent \u00eatre obtenues et il devient alors possible en les exploitant, par inversion, de caract\u00e9riser ces structures avec des pr\u00e9cisions int\u00e9ressantes sur les caract\u00e9ristiques m\u00e9caniques et dimensionnelle des couches. D\u2019autre part, les couches peuvent \u00eatre fragiles, transparentes et avec une morphologie complexe, c\u2019est pourquoi, des transducteurs interdigit\u00e9s (IDT) sont envisag\u00e9s. Ils pr\u00e9sentent deux avantages : ils peuvent \u00eatre d\u00e9port\u00e9s et ils peuvent \u00eatre larges bandes. Pour optimiser ce type de transducteurs, et en particulier leur bande passante, il est n\u00e9cessaire d\u2019\u00e9tudier diff\u00e9rentes configurations sachant qu\u2019il est notamment possible de faire varier le nombre d\u2019\u00e9lectrodes, les dimensions des \u00e9lectrodes, leurs formes et leurs espacements. Enfin, pour exciter ces ondes de surface dans une large gamme de fr\u00e9quence avec des niveaux de d\u00e9placement suffisants pour la caract\u00e9risation des couches minces et rev\u00eatements, la technique \u00e0 double Chirp spatio-temporel bas\u00e9e sur des transducteurs SAW-IDT est privil\u00e9gi\u00e9e. Dans ce travail de th\u00e8se, les potentialit\u00e9s de cette approche ont \u00e9t\u00e9 montr\u00e9es en caract\u00e9risant premi\u00e8rement des structures \u00e0 couches minces m\u00e9talliques d\u2019\u00e9paisseurs de 50 nm et plus, ensuite des couches ultraminces continues et discontinues (\u00eelots) d\u2019\u00e9paisseurs 5 \u00e0 20 nm, ainsi que les rev\u00eatements transparents de type sol-gel. La possibilit\u00e9 de caract\u00e9riser des couches de silicium m\u00e9soporeux a \u00e9t\u00e9 aussi d\u00e9montr\u00e9e.<\/p>\n<h5>Abstract:<\/h5>\n<p>This work is related to the characterization of thin films, coatings and functional surfaces (thickness, elastic constants, porosity?). Among the potential characterization methods, ultrasonic methods using surface waves (SAW) are particularly interesting. Indeed, Rayleigh-type SAW propagate on the surface of a material and the energy carried by these waves is confined under the surface on a depth of the order of a wavelength. In the case of layer-on-substrate structures, SAWs become dispersive. By exploiting this dispersion over a large frequency band, important variations of velocities can be obtained and it becomes possible to characterize these structures with interesting precisions on the mechanical and dimensional characteristics of the layers by inversion. On the other hand, the layers can be fragile, transparent and with a complex morphology, that is why, interdigital transducers (IDT) are considered. They have two advantages: they can be offset and they can be wide band. To optimize this type of transducers, and in particular their bandwidth, it is necessary to study different configurations knowing that it is possible to vary the number of electrodes, the dimensions of the electrodes, their shapes and their spacing. Finally, to excite these surface waves in a wide frequency range with sufficient displacement levels for the characterization of thin films and coatings, the double space-time Chirp technique based on SAW-IDT transducers is preferred. In this thesis, the potential of this approach has been demonstrated by characterizing first metallic thin film structures with thicknesses of 50 nm and more, then continuous and discontinuous ultra-thin films (islands) with thicknesses of 5 to 20 nm, as well as transparent sol-gel coatings. The possibility to characterize mesoporous silicon layers has also been demonstrated.<\/p>\n<p>Translated with www.DeepL.com\/Translator (free version)<\/p>\n<\/div><\/section>","protected":false},"excerpt":{"rendered":"","protected":false},"author":20,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[317],"tags":[],"class_list":["post-55304","post","type-post","status-publish","format-standard","hentry","category-these-2021"],"_links":{"self":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/55304","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/users\/20"}],"replies":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/comments?post=55304"}],"version-history":[{"count":0,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/55304\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media?parent=55304"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/categories?post=55304"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/tags?post=55304"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}