LEAP-HI: Ultra-Low Power Computing: A Disruptive Approach Through a New Integrated Nanomechanics Framework

现代社会依赖于微电子计算设备。 微处理器每秒执行数十亿次计算，使互联网，智能手机，笔记本电脑，云计算和数码相机成为可能。虽然微处理器在快速计算方面非常强大，但它们消耗大量能量。 这是因为微处理器中的数十亿个晶体管变得如此之小，以至于即使在关闭时也会泄漏电流。 新一代强大的计算硬件将需要更节能的微处理器。 晶体管是固态开关，没有移动部件。 这个领先的工程为美国的繁荣，健康和基础设施（LEAP-HI）奖支持基础研究，以取代固态晶体管与纳米机械开关，可以打开和关闭，使和断开电接触。 这些触点可以以计算机的速度运行，因为它们的尺寸非常小。 纳米机械开关触点通过垂直于界面施加的纳米牛顿力来操作。 虽然很小，但实际的接触点-纳米级粗糙-受到高应力和高电流密度的影响，产生多种降解途径。 金属材料已被用于制造电接触，但它们最终焊接在一起。这项工作的目的是调查是否硬导电氧化物涂层的金属可以用来克服这种粘附问题。该项目的智力价值在于满足力学，摩擦学和材料开发交叉点的巨大挑战：开发界面系统，不仅实现而且在数十亿至数万亿次接触循环后保持极低和稳定的粘附力和电接触电阻，并且降解最小。 为了实现这一目标，研究小组将进行氧化物导电机制的密度泛函理论计算，以及接触应力的有限元和分子动力学建模。 在实验上，不同的氧化物将使用原子力显微镜进行测试。 有前途的材料系统将被集成到原型纳米机械开关中，其功能将被测试到数万亿次循环。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Modern society relies on microelectronic computing devices. Performing billions of calculations per second, microprocessors enable the internet, smart phones, laptop computers, cloud computing and digital cameras. Although microprocessors are extremely powerful when it comes to fast computation, they consume a lot of energy. This is because the billions of transistors in microprocessors have become so small that they leak electrical current even when they are off. New generations of powerful computing hardware will require more energy efficient microprocessors. Transistors are solid state switches with no moving parts. This Leading Engineering for America's Prosperity, Health, and Infrastructure (LEAP-HI) award supports fundamental research to replace solid state transistors with nanomechanical switches that can open and close to make and break an electrical contact. These contacts can operate at the speed of computers because of their incredibly small size. Nanomechanical switch contacts are operated with nanonewton forces applied normal to the interface. Though small, the actual points of contact - nanometer-scale asperities - are subject to both high stress and high current density, creating multiple degradation pathways. Metallic materials have been used to make the electrical contacts, but they eventually weld together. The objective of this work is to investigate whether hard conducting oxide coatings on the metals can be used to overcome this adhesion problem. The intellectual merit of this project is in meeting a grand challenge at the intersection of mechanics, tribology and materials development: to develop interfacial systems that not only achieve but maintain extremely low and stable adhesion and electrical contact resistance after billions to trillions of contact cycles with minimal degradation. To accomplish this, the research team will perform density functional theory calculations of oxide conduction mechanisms, and finite element and molecular dynamics modeling of contact stresses. Experimentally, different oxides will be tested using atomic force microscopy. Promising materials systems will be integrated into prototype nanomechanical switches, and their functionality will be tested up to trillions of cycles.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.