Development of a New Transistor for Flexible Circuits

摘要标题：一种新型柔性电路用晶体管的研制这份提案描述了明尼苏达大学为了解、设计、制造和测试用于柔性电子产品的新型开关设备，即电解液门控晶体管(EGTS)而进行的跨学科合作。两位首席研究员Frisbie(化学工程和材料科学)和Ruden(电气和计算机工程)在过去十年中在晶体管开发方面有着良好的科学合作记录。在这份提案中，他们再次加入了各自的实验和计算专业知识，以了解和开发EGTS作为一种用于柔性显示器和可穿戴传感器等应用的新型设备。该项目将产生推动柔性电子学领域发展的实验和理论成果；它将支持博士生和本科生的培养；它还将为高中水平的电子材料和器件教学制作教具。在主要研究人员(PI)之前的工作中，已经确定电解液门控晶体管(EGT)在耐冲击、可弯曲的塑料基板上构建电路具有许多优势。这些优势包括：与薄膜电池兼容的低于2V的工作电压，106量级的卓越通断电流比，互补的电路设计(即p型和n型沟道)，高通态跨导1≥S/>m，接近1 MHz的快速开关速度，出色的偏置应力稳定性，良好的空气稳定性(无需封装)，以及与塑料兼容的易于近室温制造工艺。这些非常有希望的特性促使PI继续改进EGTS并开发其操作的准确计算模型，这些模型既反映了对器件物理的深刻理解，又促进了器件设计以集成到完整电路中。由于栅绝缘层包含可移动离子，因此理解EGT存在许多挑战。例如，EGT开关的机制取决于半导体通道对离子是渗透的还是不渗透的，必须构建新的晶体管模型来考虑这些差异。此外，EGTS的操作，特别是沟道载流子迁移率，取决于栅极/电解液/半导体堆叠中使用的可移动离子的类型。为了优化EGT性能，必须了解这些影响以及其他许多影响。EGTS还为改变柔性电子产品中的电路制造模式提供了大量机会。特别是，完全由电子功能液体墨水制造EGT的能力启发了PI提出了一种基于纳米压痕光刻和毛细管流的新的自对准制造策略。这种工艺被称为电子自对准毛细管流动光刻(SCALE)，将在制造p型和n型EGTS的过程中得到广泛的研究和开发。这项建议还将扩大与EGT架构兼容的材料组合，例如基于离子凝胶和陶瓷离子导体的新型栅极电解质，以及加入有机半导体和无定形氧化物作为通道材料。这项建议将在人力资源开发和创造用于教授半导体电子和材料科学的教育工具方面产生更广泛的影响。具体地说，这笔赠款将支持博士生和本科生在电子设备的制造和表征、新的微电子加工方法、新的设备架构和传感器方面的培训，即对国家劳动力发展至关重要的领域。PIS还将开发“柔性电路制造套件”的原型，这将允许高中理科学生探索微电子和材料之间的相互作用。这些套件将包括浮雕塑料基板和无毒、环保的电子墨水，这些墨水可以很容易地输送到基板上，创建电路，然后可以使用电池和电阻表等简单电源进行测试。

Abstract Title: Development of a New Transistor for Flexible CircuitsNon-technical Abstract. This proposal describes a collaborative, interdisciplinary effort at the University of Minnesota to understand, design, fabricate and test a new class of switching devices for flexible electronics, namely electrolyte gated transistors (EGTs). The two Principal Investigators, Frisbie (chemical engineering and materials science) and Ruden (electrical and computer engineering), have a strong track record of scientific collaboration in transistor development extending over the past ten years. In this proposal, they again join their respective experimental and computational expertise to understand and develop EGTs as a novel class of devices for applications such as flexible displays and wearable sensors. This project will produce experimental and theoretical results that advance the field of flexible electronics; it will support the training of PhD students and undergraduates, and it will also produce educational aids for teaching about electronic materials and devices at the high school level.Technical Abstract. In prior work by the principal investigators (PIs) it has been established that electrolyte gated transistors (EGTs) have many advantages for building circuits on impact resistant, bendable plastic substrates. These advantages include: sub-2 V operation compatible with thin film batteries, excellent ON/OFF current ratios of order 106, complementary circuit designs (i.e., p-type and n-type channels), high ON-state transconductances 1 ÝS/Ým, fast switching speeds approaching 1 MHz, excellent bias stress stability, good air stability without encapsulation, and easy, near-room-temperature fabrication procedures compatible with plastic. These very promising characteristics motivate the PIs to continue to improve EGTs and to develop accurate computational models of their operation that both reflect a deep understanding of the device physics, and facilitate device design for integration into complete circuits. There are a number of challenges associated with understanding EGTs because the gate insulator layer contains mobile ions. For example, the mechanism of EGT switching depends on whether the semiconductor channel is permeable or impermeable to ions, and new transistor models must be constructed to take account of these differences. In addition, the operation of EGTs, and in particular the channel carrier mobility, depends on the type of mobile ions employed in the gate/electrolyte/ semiconductor stack. These effects, and many others, must be understood in order to optimize EGT performance. EGTs also open up substantial opportunities for changing circuit fabrication paradigms in flexible electronics. In particular, the ability to make EGTs entirely from electronically functional liquid inks has inspired the PIs to propose a new, self-aligning fabrication strategy based on nanoimprint lithography and capillary flow. This process, termed SCALE (for Self-Aligned Capillary Flow Lithography for Electronics), will be extensively investigated and developed in connection with fabrication of p-type and n-type EGTs. The PIs will also expand the materials sets compatible with EGT architectures, e.g., new gate electrolytes based on ion gels and ceramic ion conductors, and the incorporation of both organic semiconductors and amorphous oxides as the channel materials.The broader impacts of this proposal will be in human resource development and the creation of educational tools for teaching semiconductor electronics and materials science. Specifically, this grant will support the training of PhD students and undergraduates in the fabrication and characterization of electronic devices, new microelectronics processing methods, novel device architectures, and sensors, i.e., areas that are important to national workforce development. The PIs will also develop prototype ¡§Flexible Circuit Fabrication Kits¡¨ that will allow high school science students to explore the interplay between microelectronics and materials. These kits will include embossed plastic substrates and non-toxic, environmentally friendly electronic inks that can be easily delivered to the substrates to create circuits that can then be tested using simple supplies such as a battery and a resistance meter.