{"id":60868,"date":"2023-11-20T15:07:44","date_gmt":"2023-11-20T13:07:44","guid":{"rendered":"https:\/\/www.iemn.fr\/?p=60868"},"modified":"2023-12-05T09:50:14","modified_gmt":"2023-12-05T07:50:14","slug":"these-akash-patil-thermal-characterization-of-gesbte-alloys-by-raman-thermometry-for-phase-change-memories","status":"publish","type":"post","link":"https:\/\/www.iemn.fr\/en\/agenda\/these-akash-patil-thermal-characterization-of-gesbte-alloys-by-raman-thermometry-for-phase-change-memories.html","title":{"rendered":"THESE : Akash PATIL \u2013 Thermal characterization of GeSbTe alloys by Raman thermometry for phase change memories\u201d"},"content":{"rendered":"<div id='layer_slider_1'  class='avia-layerslider main_color avia-shadow  avia-builder-el-0  el_before_av_heading  avia-builder-el-first  container_wrap sidebar_right'  style='height: 261px;'  ><div id=\"layerslider_58_ulgkx25cq0xw\" data-ls-slug=\"homepageslider\" class=\"ls-wp-container fitvidsignore ls-selectable\" style=\"width:1140px;height:260px;margin:0 auto;margin-bottom: 0px;\"><div class=\"ls-slide\" data-ls=\"duration:6000;transition2d:5;\"><img loading=\"lazy\" decoding=\"async\" width=\"2600\" height=\"270\" src=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1.jpg\" class=\"ls-bg\" alt=\"\" srcset=\"https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1.jpg 2600w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-300x31.jpg 300w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-768x80.jpg 768w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-1030x107.jpg 1030w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-1500x156.jpg 1500w, https:\/\/www.iemn.fr\/wp-content\/uploads\/2019\/01\/sliders_news1-705x73.jpg 705w\" sizes=\"auto, (max-width: 2600px) 100vw, 2600px\" \/><ls-layer style=\"font-size:14px;text-align:left;font-style:normal;text-decoration:none;text-transform:none;font-weight:700;letter-spacing:0px;border-style:solid;border-color:#000;background-position:0% 0%;background-repeat:no-repeat;width:180px;height:30px;left:0px;top:231px;line-height:32px;color:#ffffff;border-radius:6px 6px 6px 6px;padding-left:50px;background-color:rgba(0, 0, 0, 0.57);\" class=\"ls-l ls-ib-icon ls-text-layer\" data-ls=\"minfontsize:0;minmobilefontsize:0;\"><i class=\"fa fa-quote-right\" style=\"color:#ffffff;margin-right:0.8em;font-size:1em;transform:translateY( -0.125em );\"><\/i>ACTUALITES<\/ls-layer><\/div><\/div><\/div><div id='after_layer_slider_1'  class='main_color av_default_container_wrap container_wrap sidebar_right'  ><div 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-60868'><div class='entry-content-wrapper clearfix'>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-av_heading-e44836ef8e9c26e16bd5754cce6b1882\">\n#top .av-special-heading.av-av_heading-e44836ef8e9c26e16bd5754cce6b1882{\nmargin:0 0 10px 0;\npadding-bottom:4px;\n}\nbody .av-special-heading.av-av_heading-e44836ef8e9c26e16bd5754cce6b1882 .av-special-heading-tag .heading-char{\nfont-size:25px;\n}\n.av-special-heading.av-av_heading-e44836ef8e9c26e16bd5754cce6b1882 .av-subheading{\nfont-size:15px;\n}\n<\/style>\n<div  class='av-special-heading av-av_heading-e44836ef8e9c26e16bd5754cce6b1882 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\"  >THESIS: Akash PATIL - Thermal characterization of GeSbTe alloys by Raman thermometry for phase change memories<span class='special_amp'>\"<\/span><\/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>Akash PATIL<\/strong><\/p>\n<p>Defence: 27 November 2023 10:00 a.m.<strong><br \/>\n<\/strong>IEMN Amphitheatre - Central Laboratory - Villeneuve d'Ascq<\/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<h5><strong><span style=\"color: #800000;\">Jury :<br \/>\n<\/span><\/strong><\/h5>\n<p class=\"BodyofPaper\"><span class=\"ContentPasted0\" lang=\"FR\">Olivier THOMAS, Professor, IM2NP CNRS - Aix-Marseille Universit\u00e9, France - Reviewer<\/span><span class=\"ContentPasted0\" lang=\"FR\">\u00a0<\/span><\/p>\n<p class=\"BodyofPaper\"><span class=\"ContentPasted0\">llaria ZARDO, Professor, University of Basel, Switzerland - Reviewer<\/span><span class=\"ContentPasted0\">\u00a0<\/span><\/p>\n<p class=\"BodyofPaper\"><span class=\"ContentPasted0\" lang=\"FR\">Valentine GIORDANO, Research Fellow, Institut Lumi\u00e8re Mati\u00e8re, CNRS, Lyon, France - Examiner<\/span><span class=\"ContentPasted0\" lang=\"FR\">\u00a0<\/span><\/p>\n<p class=\"BodyofPaper\"><span class=\"ContentPasted0\" lang=\"FR\">Damien DELLEREUYLE, Professor, INSA Lyon, France - Examiner<\/span><span class=\"ContentPasted0\" lang=\"FR\">\u00a0<\/span><\/p>\n<p class=\"BodyofPaper\"><span class=\"ContentPasted0\" lang=\"FR\">Gabriele NAVARRO, Senior R&amp;D scientist, CEA-LETI, Grenoble, France &#8211; Examiner<\/span><span class=\"ContentPasted0\" lang=\"FR\">\u00a0<\/span><\/p>\n<p class=\"BodyofPaper\"><span class=\"ContentPasted0\" lang=\"FR\">Emmanuel DUBOIS, Research Director, IEMN, CNRS, Lille, France - Examiner<\/span><span class=\"ContentPasted0\" lang=\"FR\">\u00a0<\/span><\/p>\n<p class=\"BodyofPaper\"><span class=\"ContentPasted0\" lang=\"FR\">Jean-Fran\u00e7ois ROBILLARD, Associate Professor, Junia, Lille, France - Thesis director<\/span><span class=\"ContentPasted0\" lang=\"FR\">\u00a0<\/span><\/p>\n<p class=\"BodyofPaper\"><span class=\"ContentPasted0\" lang=\"FR\">Simon JEANNOT, Doctoral Engineer, STMicroelectronics, Crolles, France - Thesis co-director<\/span><span class=\"ContentPasted0\" lang=\"FR\">\u00a0<\/span><\/p>\n<p class=\"BodyofPaper\"><span class=\"ContentPasted0\" lang=\"FR\">Philippe BOIVIN, Doctoral Engineer, STMicroelectronics, Rousset, France - Invited<\/span><span class=\"ContentPasted0\" lang=\"FR\">\u00a0<\/span><\/p>\n<h5><strong><span style=\"color: #800000;\">\u00a0<\/span><\/strong><\/h5>\n<h5>Summary:<\/h5>\n<p>Les mat\u00e9riaux \u00e0 changement de phase (MP) sont \u00e0 la base du stockage de la m\u00e9moire depuis le d\u00e9but de leur application au stockage optique des donn\u00e9es en 1987. En 2015, la m\u00e9moire 3D XPointTM bas\u00e9e sur les mat\u00e9riaux \u00e0 changement de phase est 1000 fois plus rapide et plus endurante que la NAND, et 10 fois plus dense que la DRAM. La flexibilit\u00e9 des m\u00e9moires PM bas\u00e9es sur les chalcog\u00e9nures offre une combinaison de vitesse plus rapide, d&rsquo;endurance plus \u00e9lev\u00e9e et de stabilit\u00e9 thermique en fonction de la st\u0153chiom\u00e9trie mise en \u0153uvre. Ces caract\u00e9ristiques sont cruciales pour les m\u00e9moires non volatiles afin de combler les lacunes en mati\u00e8re de performances et de remplacer partiellement la hi\u00e9rarchie actuelle des m\u00e9moires. L&rsquo;ing\u00e9nierie approfondie des m\u00e9moires primaires bas\u00e9es sur les alliages GeSbTe (GST) a permis de r\u00e9aliser des st\u0153chiom\u00e9tries \u00e0 haute stabilit\u00e9 thermique, qui conviennent aux m\u00e9moires \u00e0 changement de phase (PCM) embarqu\u00e9es dans les MCU automobiles. Les alliages tels que le GeSbTe dop\u00e9 riche en Ge pr\u00e9sentent une r\u00e9tention des donn\u00e9es \u00e0 haute temp\u00e9rature (~300\u00b0C) en raison d&rsquo;une temp\u00e9rature de cristallisation \u00e9lev\u00e9e. Dans les PCM, la commutation r\u00e9versible entre les phases est initi\u00e9e thermiquement. Cette op\u00e9ration utilise &lt; 1 % de l&rsquo;\u00e9nergie d&rsquo;entr\u00e9e pour le changement de phase, alors que la majeure partie de l&rsquo;\u00e9nergie est perdue par d&rsquo;autres voies de dissipation de la chaleur dans la cellule PCM. Il est donc essentiel de comprendre les propri\u00e9t\u00e9s thermiques de ces mat\u00e9riaux en fonction de l&rsquo;\u00e9volution de la structure sur l&rsquo;ensemble de la temp\u00e9rature de fonctionnement de la cellule PCM pour am\u00e9liorer la compr\u00e9hension thermique et l&rsquo;optimisation de la m\u00e9moire. L&rsquo;alliage phare GST-225 a \u00e9t\u00e9 largement caract\u00e9ris\u00e9, mais l&rsquo;\u00e9tat actuel des connaissances ne permet pas de caract\u00e9riser thermiquement les st\u0153chiom\u00e9tries nouvellement con\u00e7ues.<\/p>\n<p>Des m\u00e9thodes de caract\u00e9risation thermique telles que 3w, la thermo-r\u00e9flectance et la radiom\u00e9trie photo-thermique ont \u00e9t\u00e9 mises en \u0153uvre pour la caract\u00e9risation thermique du GST. Ces m\u00e9thodes n\u00e9cessitent une microfabrication suppl\u00e9mentaire de l&rsquo;\u00e9l\u00e9ment chauffant ou du transducteur, certaines m\u00e9thodes exigeant des co\u00fbts d&rsquo;installation \u00e9lev\u00e9s accompagn\u00e9s d&rsquo;un post-traitement complexe des donn\u00e9es. Pour les mesures \u00e0 haute temp\u00e9rature (&gt;300\u00b0C), elles peuvent souffrir de l&rsquo;inter-diffusion des \u00e9l\u00e9ments du transducteur dans la TPS. Pour les GST, il est \u00e9galement crucial de surveiller l&rsquo;\u00e9volution structurelle simultan\u00e9ment, pendant la caract\u00e9risation thermique. La thermom\u00e9trie Raman est une technique de caract\u00e9risation optique qui ne n\u00e9cessite pas de microfabrication et qui peut offrir l&rsquo;avantage d&rsquo;une \u00e9tude structurelle simultan\u00e9e. Dans ce travail, nous avons \u00e9tudi\u00e9 des particules comme le GeTe, le GeSbTe riche en Ge et le GeSbTe riche en N dop\u00e9 (GGSTN) \u00e0 l&rsquo;aide de la thermom\u00e9trie Raman. Cela a \u00e9t\u00e9 possible en \u00e9tudiant la stabilit\u00e9 et la sensibilit\u00e9 des modes vibrationnels pr\u00e9sents dans les alliages \u00e0 base de GeSbTe \u00e0 la temp\u00e9rature et \u00e0 la puissance d&rsquo;entr\u00e9e du laser, \u00e0 l&rsquo;aide de simulations par \u00e9l\u00e9ments finis. Pour la premi\u00e8re fois, nous avons r\u00e9ussi \u00e0 extraire les propri\u00e9t\u00e9s thermiques de ces mat\u00e9riaux en fonction de la temp\u00e9rature et de la phase \u00e0 des temp\u00e9ratures plus \u00e9lev\u00e9es (~400\u00b0C) par thermom\u00e9trie Raman. Cela permet de mieux comprendre le comportement de ces mat\u00e9riaux \u00e0 des temp\u00e9ratures plus \u00e9lev\u00e9es et l&rsquo;effet du dopage. Cela \u00e9largit le champ d&rsquo;application des techniques de caract\u00e9risation thermique, car la thermom\u00e9trie Raman peut fournir une analyse thermique accompagn\u00e9e d&rsquo;une caract\u00e9risation structurelle simultan\u00e9e, ce qui est crucial pour les particules. Il serait d&rsquo;un int\u00e9r\u00eat progressif que les PMs ont \u00e9galement \u00e9t\u00e9 mis en \u0153uvre pour les dispositifs neuromorphiques et les commutateurs RF.<\/p>\n<h5>Abstract:<\/h5>\n<p class=\"BodyofPaper\"><span class=\"ContentPasted0\">Phase change materials (PMs) have been the basis of memory storage, since the beginning of its application for optical data storage in 1987. Fast forward to 2015, 3D XPoint<\/span><span class=\"ContentPasted0\"><sup class=\"ContentPasted0\">TM<\/sup><\/span><span class=\"ContentPasted0\"> memory product based on PMs performed 1000 times faster along with greater endurance than NAND; and 10 times denser than DRAM. The flexibility of PMs based on chalcogenides provide a combination of faster speed, higher endurance and thermal stability depending on the stoichiometry implemented. These characteristics are crucial for non-volatile memories to address the performance gaps and partially replace the existing memory hierarchy. Extensive engineering of PMs based on GeSbTe (GST) alloys led to realization of stoichiometry\u2019s with high temperature stability, which are suitable for embedded phase change memories (PCMs) application in automotive MCU. Alloys like doped Ge-rich GeSbTe presented high temperature data retention (~300\u00b0C) due to high crystallization temperature. In PCM, the reversible switching between phases is thermally initiated. This operation uses &lt; 1% of input energy for phase change, whereas most of the energy is lost via other heat dissipation pathways in the PCM cell. So, understanding of the thermal properties of these materials as a function of structural evolution over the entire operation temperature of PCM cell is crucial for better thermal understanding and optimization of the memory. The flag-ship GST-225 alloy has been extensively characterized but the current state of art falls short on thermal characterization of the newly engineered stoichiometry\u2019s. <\/span><span class=\"ContentPasted0\">\u00a0<\/span><\/p>\n<p class=\"BodyofPaper\"><span class=\"ContentPasted0\">Thermal characterization methods like 3<\/span><span class=\"ContentPasted0\">w<\/span><span class=\"ContentPasted0\">, thermo-reflectance and photo-thermal radiometry have been implemented for thermal characterization of GST. These methods require additional microfabrication of heater or transducer with some methods requiring high setup costs accompanied with complex post-processing of data. For high temperature measurement (&gt;300\u00b0C), it can suffer from inter-diffusion of transducer elements into GST. For GST, it is also crucial to monitor the structural evolution simultaneously, during thermal characterization. Raman thermometry is an optical characterization technique which requires no microfabrication and can provide an advantage of simultaneous structural investigation. In this work, we investigated PMs like GeTe,<\/span><span class=\"ContentPasted0\"> Ge-rich GeSbTe and<\/span> <span class=\"ContentPasted0\">N-doped Ge-rich GeSbTe (GGSTN) using Raman thermometry. This was possible by studying the stability and sensitivity of vibrational modes present in GeSbTe based alloys to temperature and input laser power aided with finite element simulations. We demonstrate successful extraction of temperature and phase dependent thermal properties of these materials to higher temperature (~400\u00b0C) by Raman thermometry, for the first time. It provides a better understanding of the behavior of these materials at higher temperature and the effect of doping. This extends of the scope of thermal characterization techniques as Raman thermometry can provide thermal analysis accompanied by simultaneous structural characterization which is crucial for PMs. It would be of progressive interest as PMs has also been implemented for neuromorphic devices and RF switches.<\/span><span class=\"ContentPasted0\">\u00a0<\/span><\/p>\n<\/div><\/section>","protected":false},"excerpt":{"rendered":"","protected":false},"author":20,"featured_media":60871,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[87,65,84,187],"tags":[],"class_list":["post-60868","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-agenda-en","category-agenda","category-agenda-en-en","category-annonces-these"],"_links":{"self":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/60868","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=60868"}],"version-history":[{"count":0,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/60868\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media\/60871"}],"wp:attachment":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media?parent=60868"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/categories?post=60868"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/tags?post=60868"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}