Development of a New Transistor for Flexible Circuits

摘要标题：柔性电路用新型晶体管的开发非技术摘要。该提案描述了明尼苏达大学的跨学科合作努力，以了解，设计，制造和测试一类新的柔性电子开关器件，即电解质门控晶体管（EGT）。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。在这项提案中，他们再次结合各自的实验和计算专业知识，以理解和开发EGT作为一类新型设备，用于柔性显示器和可穿戴传感器等应用。该项目将产生推进柔性电子领域的实验和理论成果，支持博士生和本科生的培养，并将为高中阶段的电子材料和设备教学制作教育辅助工具。技术摘要在主要研究者（PI）的先前工作中，已经确定电解质门控晶体管（EGT）对于在抗冲击、可弯曲的塑料基板上构建电路具有许多优点。这些优势包括：与薄膜电池兼容的低于2 V的操作，106量级的优异的ON/OFF电流比，互补的电路设计（即，p型和n型沟道）、1 μ S/μ m的高导通跨导、接近1 MHz的快速开关速度、出色的偏置应力稳定性、无需封装的良好空气稳定性以及与塑料兼容的接近室温的简易制造工艺。这些非常有前途的特性促使PI继续改进EGT并开发其操作的精确计算模型，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，以便集成到完整的电路中。由于栅极绝缘体层含有移动的离子，因此存在与理解EGT相关联的许多挑战。例如，EGT开关的机制取决于半导体沟道对离子是可渗透的还是不可渗透的，必须构建新的晶体管模型来考虑这些差异。此外，EGT的操作，特别是沟道载流子迁移率，取决于栅极/电解质/半导体叠层中采用的移动的离子的类型。为了优化EGT性能，必须了解这些效应和许多其他效应。EGT还为改变柔性电子产品中的电路制造范例开辟了大量机会。特别是，完全由电子功能液体油墨制造EGT的能力激发了PI提出一种基于纳米压印光刻和毛细管流动的新的自对准制造策略。这个过程，被称为SCALE（电子自对准毛细管流光刻），将被广泛研究和开发与p型和n型EGT的制造。PI还将扩展与EGT架构兼容的材料集，例如，基于离子凝胶和陶瓷离子导体的新型栅极电解质，以及有机半导体和非晶氧化物作为沟道材料的结合，这一提议的更广泛影响将是人力资源开发和创建用于教授半导体电子学和材料科学的教育工具。具体而言，该补助金将支持博士生和本科生在电子设备的制造和表征，新的微电子处理方法，新颖的设备架构和传感器，即，对国家劳动力发展至关重要的领域。PI还将开发原型“柔性电路制造工具包”，使高中理科学生能够探索微电子和材料之间的相互作用。这些套件将包括压花塑料基板和无毒，环保的电子墨水，可以很容易地交付到基板，以创建电路，然后可以使用简单的供应，如电池和电阻计进行测试。

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.