{"id":71620,"date":"2024-12-09T17:31:07","date_gmt":"2024-12-09T15:31:07","guid":{"rendered":"https:\/\/www.iemn.fr\/?p=71620"},"modified":"2024-12-09T17:31:07","modified_gmt":"2024-12-09T15:31:07","slug":"these-geoffrey-lezier-2","status":"publish","type":"post","link":"https:\/\/www.iemn.fr\/en\/a-la-une\/these-geoffrey-lezier-2.html","title":{"rendered":"Francois Grandpierron's thesis: \"Design, Fabrication and Simulation of next generation robust GaN HEMTs for millimeter-wave applications\" on 17\/12 14h00"},"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_1f1wj6taerrzj\" 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-71620'><div class='entry-content-wrapper clearfix'>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-k5dohoxw-cf7f0f34619d0dfdbb98f9e05c75c6b1\">\n#top .av-special-heading.av-k5dohoxw-cf7f0f34619d0dfdbb98f9e05c75c6b1{\nmargin:0 0 10px 0;\npadding-bottom:4px;\n}\nbody .av-special-heading.av-k5dohoxw-cf7f0f34619d0dfdbb98f9e05c75c6b1 .av-special-heading-tag .heading-char{\nfont-size:25px;\n}\n.av-special-heading.av-k5dohoxw-cf7f0f34619d0dfdbb98f9e05c75c6b1 .av-subheading{\nfont-size:15px;\n}\n<\/style>\n<div  class='av-special-heading av-k5dohoxw-cf7f0f34619d0dfdbb98f9e05c75c6b1 av-special-heading-h4  avia-builder-el-1  el_after_av_layerslider  el_before_av_hr  avia-builder-el-first  av-linked-heading'><h4 class='av-special-heading-tag'  itemprop=\"headline\"  >Francois Grandpierron's thesis: \"Design, Fabrication and Simulation of next generation robust GaN HEMTs for millimeter-wave applications\" 17 December at 2pm<\/h4><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-fd5f2e9d63bf552d6910d12f255eb26e'   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>Francois Grandpierron's thesis<br \/>\n<\/strong><\/p>\n<p>Defence: 17 December 14:00<strong><br \/>\n<\/strong>IEMN Amphitheatre<\/p>\n<\/div><\/section>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-jtefqx33-6db969b2e204313ebd62331ed4fc69ec\">\n#top .av_textblock_section.av-jtefqx33-6db969b2e204313ebd62331ed4fc69ec .avia_textblock{\nfont-size:15px;\n}\n<\/style>\n<section  class='av_textblock_section av-jtefqx33-6db969b2e204313ebd62331ed4fc69ec'   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<\/span><\/strong><\/h5>\n<p>Thesis Director<br \/>\nMr. Farid MEDJDOUB CNRS scientist (IEMN, France)<\/p>\n<p>Reviewers<br \/>\nMrs. Nadine COLLAERT (Professor, Vrije Universiteit Brussel)<br \/>\nMr. Jean-Pierre RASKIN (Professor, UC Louvain)<\/p>\n<p>Examiners<br \/>\nMr. Didier THERON (DR CNRS, IEMN)<br \/>\nMr. Cesar RODA NEVE (Program manager, SOITEC)<br \/>\nMr. Jean-Marc TANGUY (Engineer, DGA)<\/p>\n<p>Invited<br \/>\nMr. Didier FLORIOT (Thales technical director)<\/p>\n<h5><strong><span style=\"color: #800000;\">\u00a0<\/span><\/strong>Summary:<\/h5>\n<p>In recent years, significant progress has been made with GaN high electron mobility transistors (HEMTs) to advance the next generation of 5G networks, radar systems and satellite communications. However, to further improve power amplification and high-frequency operation (&gt;30 GHz), innovative architectures have been developed. These designs feature redesigned structures, including sub-150nm gate lengths, thinner barrier layers or optimised epitaxial layers. Several research groups have achieved impressive results, with high added power efficiency (PAE &gt; 50 %) and high output power (POUT &gt; 3 W\/mm), in frequency ranges from Ka-band (30 GHz) to W-band (94 GHz). Despite this progress, the reliability of short devices remains a major challenge due to the high electric field, self-heating and electron trapping effects. This research integrates device fabrication, structural and electrical characterisation and TCAD simulations to provide state-of-the-art information in this area. One of the most promising technologies, the degraded AlGaN channel HEMT, has been studied using advanced simulations to better understand its unique properties. In addition, an optimised buffer architecture using an AlGaN back barrier and an ultra-thin AlN barrier has made it possible to achieve peak power performance at 40 GHz in fabricated devices. Finally, a new unbuffered architecture featuring an ultra-thin AlGaN barrier was also investigated, with promising results that could rival existing technologies. Short-term reliability tests were carried out to identify the main shortcomings and guide future developments.<\/p>\n<h5 align=\"justify\"><strong>Abstract:<\/strong><\/h5>\n<p>In recent years, significant progress has been achieved with GaN high electron mobility transistors (HEMTs) in advancing the next generation of 5G networks, radar systems, and satellite communications. However, to further enhance power amplification and high-frequency operation (&gt;30 GHz), innovative architectures have been developed. These designs feature reengineered structures, including sub-150 nm gate lengths, thinner barrier layers, or optimized epitaxial layers. Several research groups have demonstrated impressive results, achieving high power-added efficiency (PAE &gt; 50%) with substantial high output power (POUT &gt; 3 W\/mm), across frequency ranges from the Ka-band (30 GHz) to the W-band (94 GHz). Despite these advancements, the reliability of short devices remains a significant challenge due to high electric field, self-heating, and electron trapping effects. This research integrates device fabrication, structural and electrical characterizations, and TCAD simulations to provide cutting-edge insights in this field. One of the most promising technologies, the graded AlGaN channel HEMT has been explored through advanced simulations to better understand its unique properties. Furthermore, an optimized buffer architecture using an AlGaN back barrier and an ultra-thin AlN barrier has enabled state-of-the-art power performance at 40 GHz in fabricated devices. Finally, a novel buffer-free architecture featuring an ultra-thin AlGaN barrier has also been investigated, showing promising results that may rival existing technologies. Short-term reliability tests have been conducted to identify key shortcomings and guide future development.<\/p>\n<\/div><\/section>","protected":false},"excerpt":{"rendered":"","protected":false},"author":20,"featured_media":71447,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,8,319,65,87,84],"tags":[],"class_list":["post-71620","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-a-la-une","category-actualites","category-actualites2022","category-agenda","category-agenda-en","category-agenda-en-en"],"_links":{"self":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/71620","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=71620"}],"version-history":[{"count":0,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/posts\/71620\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media\/71447"}],"wp:attachment":[{"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/media?parent=71620"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/categories?post=71620"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.iemn.fr\/en\/wp-json\/wp\/v2\/tags?post=71620"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}