CAREER: Phase-change memories and electro-thermal effects at nanoscale

目的：1）通过实验和计算研究，调查发生在纳米级相变存储器器件的电热现象。2）计算和实验研究积极规模的相变存储器单元设计，包括访问设备和紧凑的复合单元的方法。3）支持研究生和本科生教育，以及推广活动，在电子器件，电热效应，纳米科学和纳米技术。 智力优势：相变存储器是一种非易失性电阻存储器技术，其具有可扩展到10 nm范围的潜力，具有快速访问时间、高封装密度和低能耗。相变存储器利用一类材料，其可以通过快速熔化或退火在低电阻结晶状态和高电阻非晶态之间可逆地改变。相变存储器与硅电子器件的集成用于高密度存储和高性能低功率存储，需要跨物理学、材料科学、器件工程和电路设计的集成方法。本研究是与IBM合作的一项综合研究计划，利用有限元模拟和相变存储器材料、测试结构和器件的实验来填补这些领域的知识空白，使相变存储器成为主流存储器技术。有限元模拟将用于理解电热现象的贡献，实验设计和相变存储器单元的设计。这些实验将用于提取重要的物理参数并证明原理。与计算研究相结合的实验将用于提取无法直接测量的重要物理参数，探测尚未很好理解的电热过程，并设计新颖的电池结构。相变元件与接入设备将作为一个整体进行研究，和潜在的复合设备的接入设备是相变元件的一个组成部分，将调查其潜在的高密度阵列。制造过程将在IBM沃森研究中心通过现有的合作安排使用最先进的工具进行。更广泛的影响：该项目的研究结果将使人们更好地了解所有利用电热效应或受电热效应影响的设备，如其他电阻存储技术、微型热电发电机和纳米晶体管。研究结果将发表在科学期刊和在线（如nanoHub、thermalHub）上。研究生和本科生将有机会获得IBM沃森研究中心的设施和专业知识，将获得纳米纤维，纳米电子器件设计和表征的经验，并将了解相变，热电传输，仪器和数值建模。研究结果将用于推广活动，研究工作将与康涅狄格大学的本科和研究生课程相结合。

Objectives:1) To investigate electro-thermal phenomena that take place in nanometer scale phase change memory devices through experimental and computational studies.2) To computationally and experimentally investigate aggressively scaled phase-change memory cell designs including access devices and compact composite cell approaches.3) To support graduate and undergraduate education, as well as outreach activities, in electronic devices, electro-thermal effects, nanoscience and nanotechnology. Intellectual Merit: Phase change memory is a non-volatile resistive memory technology that has shown potential for scalability down to 10 nm range with fast access times, high packing density and low energy consumption. Phase change memory makes use of a class of materials that can be reversibly changed between low-resistance crystalline and high-resistance amorphous states through rapid melting or annealing. Integration of phase change memory with silicon electronics for high-density storage and high-performance low-power storage requires an integrated approach bridging across physics, materials science, device engineering and circuit design. The proposed work is an integrated research program in collaboration with IBM, utilizing finite element simulations and experiments on phase change memory materials, test structures and devices to close the gaps of knowledge across these fields to make phase change memory a main stream memory technology.Finite element simulations will be used to understand the contribution of electro-thermal phenomena, design of experiments and design of phase change memory cells. The experiments will be used to extract important physical parameters and demonstrate proof of principle. Experiments integrated with computational studies will be used to extract important physical parameters that cannot be measured directly, probe electro-thermal processes that are not very well understood and design novel cell structures. Phase-change elements with access devices will be studied as a whole, and potential composite devices where the access device is an integral part of the phase-change element will be investigated for their potential for high-density arrays. The fabrication processes will be performed at IBM Watson Research Center using state-of-the-art tools through an existing collaborative arrangement. Materials and device characterization, and experimental and computational studies will be carried out at University of Connecticut.Broader impacts: The findings from this project will provide for better understanding of all devices that either utilize or are affected by electro-thermal effects such as other resistive memory technologies, micro thermoelectric generators and nanoscale transistors. The results will be published in scientific journals and online (e.g. nanoHub, thermalHub). Graduate and undergraduate students will have access to the facilities and expertise at IBM Watson Research Center, will get experience on nanofabrication, nanoelectronic device design and characterization, and will learn about phase changes, thermoelectric transport, instrumentation and numerical modeling. Findings will be used for outreach activities and the research effort will be integrated with undergraduate and graduate level courses at University of Connecticut.