N1005 IBM Research: Carbon

<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgOkwx8dgZjEq2tT0d2JMt66-5m-lAMSfRN8mgil7BTzR-6LqGyHRX27dBcSBIBlVF2DBgrifG8kfqup1P3BlTl3Kt4bJbgZvOs3wzd8OpLYxEHP84nHL6gQcSj_iH7VZJ-2kQwJxbJbt0/s1600/ncomms9600-f3.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgOkwx8dgZjEq2tT0d2JMt66-5m-lAMSfRN8mgil7BTzR-6LqGyHRX27dBcSBIBlVF2DBgrifG8kfqup1P3BlTl3Kt4bJbgZvOs3wzd8OpLYxEHP84nHL6gQcSj_iH7VZJ-2kQwJxbJbt0/s320/ncomms9600-f3.jpg" width="271" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">    <span style="font-family: AdvOTcb88df00; font-size: 8pt;">Memory devices based on a-CO</span><span style="font-family: 'AdvOTe75a9404.I'; font-size: 6pt; vertical-align: -1pt;">x</span><span style="font-family: AdvOTcb88df00; font-size: 8pt;">.  Credit: Nature Comms</span></td></tr></tbody></table><div style="border: 0px; font-family: Arial, sans-serif; outline: 0px; padding: 6px 0px; vertical-align: baseline;"><i><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;">Memory that constitutes resistance as a state variable encompasses a broad range of materials and switching mechanisms</span></i><br /><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;">Of these memory technologies, some, namely magnetic random access memory (MRAM), phase-change memory (PCM) and reduction/oxidation (redox) memories, have received more attention from the scientific community and the semiconductor industry and are thus in a more advanced state of research and/or development.</span></div><div style="border: 0px; font-family: Arial, sans-serif; outline: 0px; padding: 6px 0px; vertical-align: baseline;"><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;">At IBM Research – Zurich, we are pursuing yet another resistive memory concept based on carbon. Carbon-based memory could be a significant complement to the rapid advances in carbon-based nano-electronics. This could pave the way for potential all-carbon computing devices of the future. </span></div><div style="border: 0px; font-family: Arial, sans-serif; outline: 0px; padding: 6px 0px; vertical-align: baseline;"><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;">The elemental nature of carbon would enable a carbon-based memory to be scaled down to very small feature sizes and to be immune to compositional changes that typically plague alternate multi-elemental non-volatile memory materials.</span><br /><a name="more"></a><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;">In addition, the high resilience of carbon to a variety of external stimuli would ensure robustness and endurance of such a carbon-based memory.</span></div><div style="border: 0px; font-family: Arial, sans-serif; outline: 0px; padding: 6px 0px; vertical-align: baseline;"><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;">Today, a team of scientists based in Switzerland published a significant milestone in the prestigious peer-review journal <i><a href="http://www.nature.com/ncomms/2015/151023/ncomms9600/abs/ncomms9600.html">Nature Communications</a> </i>on the development of carbon memory. I interviewed three of the paper's authors to gain some further insight on their research.</span></div><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjgjTOCltMcWCAgOILiPtAfDtM_BumfTng_3gIyfaUUQwjMC5msWYwUf61bzv0nX9w-tQ0O1xZeK_Rfk-ABSFYGnBMg1surI0fIU1NhYJH7C-azoX5_huFkrcSJASRhvuAgqSzqXi_U5Vc/s1600/Unknown.jpeg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjgjTOCltMcWCAgOILiPtAfDtM_BumfTng_3gIyfaUUQwjMC5msWYwUf61bzv0nX9w-tQ0O1xZeK_Rfk-ABSFYGnBMg1surI0fIU1NhYJH7C-azoX5_huFkrcSJASRhvuAgqSzqXi_U5Vc/s1600/Unknown.jpeg" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Claudia Santini</td></tr></tbody></table><div class="MsoNormal" style="margin-bottom: 0.0001pt; text-align: center;"><br /></div><div class="MsoNormal" style="margin-bottom: 0.0001pt;"><b><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;">You compare oxygenated amorphous carbon with graphite oxide in the opening abstract of the paper. Why?</span></b><br /><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><a href="https://ch.linkedin.com/in/claudiasantini">Claudia Santini</a>: <i>Graphite and graphene oxide have been widely investigated in the past years for resistive memory applications.</i></span><br /><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><i>However, their performance fell short of the expectations and, moreover, the fabrication methods of these materials are somehow unreliable and do not allow properly controlling their properties on wafer-scale.</i></span></div><div class="MsoNormal" style="margin-bottom: 0.0001pt;"><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><i>This is a clear disadvantage for electronics applications. On the other hand, in our work we demonstrate that oxygenated amorphous carbon, which is a material made of carbon and oxygen like graphite/graphene oxide, can be produced by a much simpler method, its properties can be controlled on a wafer scale and outperforms graphite/graphene oxide for resistive memory applications.</i></span><span style="font-family: Helv, sans-serif;"><span style="font-size: large;"><b><br /></b></span></span></div><div class="MsoNormal" style="margin-bottom: 0.0001pt;"><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><b>What inspired the use of oxygenated amorphous carbon?</b></span></div><div class="MsoNormal" style="margin-bottom: 0.0001pt;"><br /></div><div class="MsoNormal" style="margin-bottom: 0.0001pt;"><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><i>CS: A relatively simple idea. Amorphous carbon memories have been investigated in the latest years by some research groups including the group working with <a href="http://researcher.watson.ibm.com/researcher/view.php?person=zurich-ele">Evangelos Eleftheriou</a> at IBM. These memories have always shown limited endurance due to the difficulty to break the conductive carbon filaments that are thought to be responsible for the low resistance state.</i></span><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><i> </i></span><br /><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><i>As it is known that carbon-based materials break down by Joule heating at much lower current densities when exposed to oxygen, I thought that the addition of oxygen as a dopant to carbon-based memories could facilitate the breaking of the carbon filaments and improve the memory endurance.</i></span><br /><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><i>This was correct and we were able to demonstrate endurance higher than 10</i></span><i><sup style="font-family: Helv, sans-serif;">4</sup><span style="font-family: Helv, sans-serif;"> cycles without current control devices. Of course, the switching mechanism we finally demonstrated was more complex than our initial idea, but the general concept was correct.</span></i></div><div class="MsoNormal" style="margin-bottom: 0.0001pt;"><br /></div><div class="MsoNormal" style="margin-bottom: 0.0001pt;"><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><b>This question is for <a href="http://researcher.watson.ibm.com/researcher/view.php?person=zurich-ASE">Abu Sebastian</a> and <a href="http://researcher.ibm.com/researcher/view.php?person=zurich-WKO">Wabe Koelmans</a>: How would you compare oxygenated amorphous carbon with your recent paper on <a href="http://ibmresearchnews.blogspot.ch/2015/09/eureka-moments-lead-to-radical-new.html">Projected Memory</a>?</b></span></div><div class="MsoNormal" style="margin-bottom: 0.0001pt;"><br /></div><div class="MsoNormal" style="margin-bottom: 0.0001pt;"><table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: right; margin-left: 1em; text-align: right;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeN58vzFCN6HgaCRNPFBFctm1qBA7DBP9LS7LXQIM2vT4GrLerN8UvCybC-nH1iqj8kMlqJeRfyUu9DHB5P1kX2_dxr9IiNmE5lz5Ndf2p19N9aIIN9oByaS1uKkMnRnqZwX8ZJr2K47U/s1600/naturecoms.jpg" imageanchor="1" style="clear: right; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="236" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeN58vzFCN6HgaCRNPFBFctm1qBA7DBP9LS7LXQIM2vT4GrLerN8UvCybC-nH1iqj8kMlqJeRfyUu9DHB5P1kX2_dxr9IiNmE5lz5Ndf2p19N9aIIN9oByaS1uKkMnRnqZwX8ZJr2K47U/s320/naturecoms.jpg" width="320" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;"><span style="font-family: AdvOTcb88df00; font-size: 8pt;">Comparison of the fabrication methods of GO and a-CO</span><span style="font-family: 'AdvOTe75a9404.I'; font-size: 6pt; vertical-align: -1pt;">x</span><span style="font-family: AdvOTcb88df00; font-size: 8pt;">. <br />Credit: Nature Communications </span></td></tr></tbody></table><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;">Abu Sebastian: <i>Both of them are non-volatile memory (NVM) candidates. In both cases we use resistance as the state variable to store information.</i> </span><br /><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;">Projected memory is a radical rethink of a phase change memory device where we mitigate or eliminated several drawbacks of conventional phase change memory technology.<i> </i></span><br /><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><i>PCM is arguably the most advanced NVM technology and projected PCM will give significant impetus to that.  Compared to phase change memory, carbon-based memory is at its infancy. But, carbon-based memory has some unique advantages.</i> </span></div><div class="MsoNormal" style="margin-bottom: 0.0001pt;"><br /><i><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;">For example, it uses a very common element as the memory material, could possibly scale to very small dimensions, can integrate seamlessly with other carbon-based electronic devices such as logic devices and interconnects. Hence in some applications, carbon-based memory and oxygenated carbon memory in particular could be much better suited.</span></i><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><b> </b></span><br /><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><b>What was the biggest challenge?</b></span></div><div class="MsoNormal" style="margin-bottom: 0.0001pt;"><br /></div><div class="MsoNormal" style="margin-bottom: 0.0001pt;"><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><i>CS: It is not obvious to mix carbon and oxygen and make a memory out of it, which needs to withstand thousands switching cycles and it took some time before being able to convince ourselves that this could work.</i></span><br /><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><i>But the biggest technical challenges were to produce the material and assess the reproducibility of the process and to study and understand the switching mechanism in oxygenated amorphous carbon memories.</i></span><br /><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><i>Generally, the switching mechanism in resistive memories is an object of a long debate. The difficulty to study this mechanism comes from the fact that the switching occurs at sub-nanometer scale and it is very challenging to visualize and analyze. Thanks to a careful electrical characterization and a detailed microscopy and spectroscopy analysis we have been able to shed some light on it.</i> </span><br /><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;">Wabe Koelmans: <i>Inherent variability in resistive switching devices (cell-to-cell and cycle-to-cycle).</i><b> </b></span><br /><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><b>When do you think carbon-based electronics will enter the market?</b></span></div><div class="MsoNormal" style="margin-bottom: 0.0001pt;"><br /><i><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;">WK: There is a company called <a href="http://nantero.com/">Nantero</a> working towards a commercial memory product based on carbon as a switching material. It is unclear what their timeline is for a commercial product. As of now, there are no commercial carbon-based memory chips available.</span></i></div><div class="MsoNormal" style="margin-bottom: 0.0001pt;"><br /></div><div class="MsoNormal" style="margin-bottom: 0.0001pt;"><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><i>CS: Carbon-based electronics has driven a lot of interest in research in the latest years. Several electronics devices based on carbon allotropes have been demonstrated: interconnects, transistors, memories. As it was stated about one year ago by one IBM colleague, <a href="http://ibmresearchnews.blogspot.ch/2012/10/carbon-nanotubes-to-keep-up-with-moores.html">Wilfried Haensch</a>, according to the semiconductor industry’s roadmap, transistors will need to have features as small as 5 nm already in 2020 and this is when carbon is expected and will have to replace traditional silicon electronics.</i><b> </b></span><br /><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><b>Claudia, you recently joined a new company. Are you continuing this research?</b></span><br /><br /></div><i><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;">CS: Not exactly. Optotune is a company working in the field of deformable optics so we investigate new polymer and carbon based materials for optical rather than electronics applications. Very soon we will start working on a new challenging and interdisciplinary project where an interesting mixture of MEMS, polymer and biomedical technologies will be developed to launch a new product.</span></i><br /><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><i>Based on carbon? It can be, but you will know more about it in the future.</i><i><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;"> </span></i></span><br /><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><i><span style="font-family: Helvetica Neue, Arial, Helvetica, sans-serif;">Oxygenated amorphous carbon for resistive memory applications, Claudia A. Santini, Abu Sebastian, Chiara Marchiori, Vara Prasad Jonnalagadda, Laurent Dellmann, Wabe W. Koelmans, Marta D. Rossell, Christophe P. Rossel& Evangelos Eleftheriou, <span style="color: #333333; text-transform: capitalize;">Nature Communications, </span>6<span style="color: #333333;">, </span><span style="color: #333333;">Article number: </span><span style="color: #333333;">8600,</span><span style="color: #333333;">doi:10.1038/ncomms9600</span> </span></i></span><br /><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"><span style="font-family: "HelvNeue Light for IBM",sans-serif; font-size: 13.0pt; line-height: 107%;"></span></span>

Memory devices based on a-CO x . Credit: Nature Comms Memory that constitutes resistance as a state variable encompasses a broad range...