Collaborative Research: FuSe: Polymer SWIR Photodiodes for Focal Plane Arrays

北卡罗莱纳州立大学的frank So、Veena Misra、Margaret Blanchard和Kenan Gundogdu教授以及北卡罗来纳大学教堂山分校的Wei You教授得到了美国国家科学基金会未来半导体（FuSe）项目的支持，开发了一种涉及材料、设备和系统技术的协同设计方法。在短波红外（SWIR）区域具有响应的低带隙共轭聚合物将被合成并用于红外成像应用的聚合物光电二极管传感器。目前最先进的SWIR成像依赖于由无机合金制成的传感器，这种传感器与CMOS芯片不兼容，而且生产成本极高，图像分辨率有限。聚合物系统将采用与CMOS技术完全兼容的加工技术制造，能够以更低的生产成本提供更高的图像分辨率和性能。SWIR成像系统的成功开发将导致成像系统的范式转变，这是目前可用的成像技术无法实现的。该研究小组正在与工业合作伙伴SWIR Vision Systems合作，展示一种低成本的SWIR原型相机。除了推进成像技术外，项目成果还将对其他实际应用产生广泛影响，包括医疗诊断、安全和通信。在进行拟议研究的过程中，将招募来自北卡罗来纳州立大学和当地社区学院的不同本科生群体作为“FuSe研究员”，为未来的微芯片制造职业进行培训，并将开展针对当地高中的一系列外展活动，包括实验室参观和特别演示。该项目的目标是开发用于短波红外（SWIR）成像应用的有机聚合物光电二极管。当前最先进的SWIR成像需要用InGaAs制成的传感器与CMOS读出芯片异质集成。虽然目前的传感器是一项成熟的技术，但InGaAs与硅的不兼容性导致了高生产成本和有限的相机分辨率。为了缓解这些挑战，低带隙共轭聚合物将通过简单的溶液处理和真空沉积来制造光电二极管。由于这些光电二极管阵列的处理与标准硅制造设备中的硅完全兼容，因此所得到的SWIR焦平面阵列与硅背板的异构集成将是直接的。项目内容包括：1)设计和合成具有SWIR吸收带的共轭聚合物；单组分和给体聚合物/分子受体体系中光载流子生成和动力学的光物理表征3)光电二极管的设计、制造及光电性能表征；4)兼容Si背板工艺的器件异质制造与表征，SWIR相机原型焦平面阵列制造工艺开发；以及DFT和ML计算计算，为实验提供信息。该奖项反映了美国国家科学基金会的法定使命，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。

Professors Franky So, Veena Misra, Margaret Blanchard and Kenan Gundogdu of North Carolina State University and Professor Wei You of University of North Carolina at Chapel Hill are supported by the NSF Future of Semiconductors (FuSe) Program to develop a co-design approach that involves materials, devices, and systems technology. Low bandgap conjugated polymers with response in the shortwave infrared (SWIR) region will be synthesized and used as polymeric photodiode sensors for infrared imaging applications. Current state-of-the-art SWIR imaging relies on sensors made from inorganic alloys, which are incompatible with CMOS chips and suffer from extremely high production costs and limited image resolution. The polymeric systems, which will be fabricated using processing techniques fully compatible with CMOS technology, are posed to deliver higher image resolution and performance at a much-reduced production cost. Success in developing a SWIR imaging systems will result in a paradigm shift in imaging systems that is not possible with currently available imaging technologies. The research team is teaming with an industrial partner, SWIR Vision Systems, to demonstrate a low-cost SWIR prototype camera. In addition to advancing imaging technology, the project outcomes will be broadly impactful on other practical applications, including medical diagnostics, security, and communications. During the course of conducting the proposed research a diverse group of undergraduate students from North Carolina State University and local community colleges will be recruited as “FuSe Fellows” to be trained for future careers in microchip manufacturing and a number of outreach activities geared towards local high schools, including lab tours and special demonstrations, will be conducted. The goal of this project is to develop organic polymer-based photodiodes for short-wave infrared (SWIR) imaging applications. Current state-of-the-art SWIR imaging requires sensors made with InGaAs heterogeneously integrated with CMOS readout chips. While the current sensor is a proven technology, the incompatibility of InGaAs with silicon leads to high production costs and limited camera resolution. To mitigate these challenges, low-bandgap conjugated polymers will be used to fabricate photodiodes through simple solution processing and vacuum deposition. As the processing of these photodiode arrays is fully compatible with silicon in a standard silicon fabrication facility, heterogeneous integration of the resulting SWIR focal plane arrays with the silicon backplane will be straightforward. The project involves: 1) the design and synthesis of conjugated polymers with SWIR absorption bands; photophysical characterization of photocarrier generation and dynamics in single component and donor polymer/molecular acceptor systems; 3) photodiode design, fabrication and characterization of optical and electrical properties; 4) heterogeneous fabrication and characterization of devices compatible with Si backplane process and development of a process to fabricate focal plane array for SWIR camera prototypes; and DFT and ML computational calculations to inform the experiments.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.