Low-Voltage High-Frequency Vertical Organic Transistors

有机场效应晶体管(OFET)有望实现低成本、灵活的电子产品。在对工作原则的基本理解的推动下，业绩有了显著的改善。然而，有机半导体的低载流子迁移率仍然限制了OFET的应用，导致工作频率和驱动电流较低，这使得许多应用变得遥不可及。通过将沟道长度扩展到亚微米区域，可以提高OFET的性能，但这涉及昂贵的结构技术，并且考虑到有机电子作为一种低成本技术的优势，这是一种抑制。在这个项目中，我们提出了一种新的技术来克服传统有机晶体管的这些限制。与传统OFET的水平结构不同，晶体管是垂直结构的。这允许通过有机或金属层的厚度来定义沟道长度，这些厚度可以以纳米精度控制。因此，有可能在不需要昂贵的结构技术的情况下，将沟道长度大幅缩减到100 nm以下。该项目将涵盖实现这种垂直技术所需的所有研究方面，从材料科学、器件优化到电路设计。特别是，该项目旨在a)通过掺杂IAPP开发的源/漏接触和高级绝缘层(IAPP/LEO，IHM/BARTHA)来提高IAPP已经开发的垂直有机晶体管的性能，b)表征和改进这些晶体管的高频性能(IAPP/Lüssem，CCN/Ellinger)，以及c)实现工作在高频下的全有机放大器(CCN/Ellinger，IAPP/Lüssem)。这四个合作伙伴拥有挑战这一要求苛刻的项目所需的独特专业知识组合。IAPP(Leo教授，L博士)发展了几个垂直晶体管概念，并以其掺杂技术而闻名，这对垂直OFET的改进至关重要。IHM是原子和分子层沉积(ALD和MLD)方面的专家，该技术将用于开发新型超薄有机/无机纳米杂化层，用作栅绝缘层，以实现低电压操作。最后，CCN致力于使用cmos和Bicmos技术以及先进的“超越摩尔”技术，如碳纳米管、纳米线和有机与聚合物器件来设计集成电路。CCN的专业知识对于有机放大器的设计和晶体管的高频表征至关重要。这些小组在应用物理、材料科学、电气工程和电路设计领域的合作将带来有机晶体管研究的新视角，以及使有机电子学取得突破的新的、非传统的解决方案。

Organic field effect transistors (OFETs) hold the promise of enabling a low cost, flexible electronics. Driven by a fundamental understanding of the working principles, a significant improvement in performance has been reached. However, OFETs are still limited by the low charge carrier mobility of organic semiconductors, leading to low operational frequencies and driving currents, which render many applications out of reach. The performance of OFETs could be increased by scaling the channel length into the sub-micrometer region, which however involves costly structuring techniques and is inhibitive considering the strengths of organic electronics as a low cost technology.In this project we propose a novel technology to overcome these limits of conventional organic transistors. Instead of the horizontal structure of conventional OFETs, the transistors are structured vertically. This allows defining the channel length by the thickness of organic or metallic layers which can be controlled with nanometer precision. Thus, it is possible to aggressively scale the channel length down to the sub 100nm region without the need for costly structuring techniques.The project will cover all research aspects needed to enable such a vertical technology, ranging from materials science, device optimization, to circuit design. In particular, the project aims at a) improving the performance of vertical organic transistors already developed by IAPP by doping the source/drain contacts and advanced insulating layers developed by IHM (IAPP/Leo, IHM/Bartha), b) characterizing and improving the high-frequency performance of these transistors (IAPP/Lüssem, CCN/Ellinger), and c) realizing a fully organic amplifier operating at high frequencies (CCN/Ellinger, IAPP/Lüssem). The four partners have a unique combination of expertise needed to challenge this demanding project. The IAPP (Prof. Leo, Dr. Lüssem) developed several vertical transistor concepts and is well known for its doping technology, which is essential for the improvement of vertical OFETs. The IHM is an expert in atomic and molecular layer deposition (ALD and MLD), which will be used to develop novel ultrathin organic/inorganic nanohybride layers used as gate insulator to allow for low voltage operation. Finally the CCN is devoted to the design of integrated circuits using CMOS and BiCMOS technologies as well as advanced "Beyond and Beside Moore" technologies like carbon nano tubes, nanowires and organic & polymer devices. The expertise of the CCN is essential for the design of the organic amplifier and the high-frequency characterization of the transistors.The cooperation of these groups across the boundaries of applied physics, materials science, electrical engineering, and circuit design will lead to novel perspectives in research in organic transistors and to novel, unconventional solutions that enable a breakthrough in organic electronics.