晶格匹配InAs/GaAsSb二类超晶格甚长波红外探测器的暗电流抑制研究

甚长波红外谱段主要覆盖室温、低温目标的辐射峰值波长，是天基红外技术发展的战略性波段。尤其近年来随着武器装备向信息化发展，对深空低温目标、远距离目标的识别需求不断增加，迫切要求将红外探测器的探测波段扩展至甚长波领域，多项国家重大任务中都对高灵敏甚长波焦平面提出了迫切需求。然而，由于禁带宽度窄，暗电流一直是制约甚长波焦平面性能提升的关键因素。本项目拟开展超晶格甚长波红外探测器的暗电流抑制研究。选择晶格匹配、缺陷密度低的InAs/GaAsSb二类超晶格材料体系，降低SRH复合；通过能带剪裁引入异质势垒结构，特别提出势垒和吸收区掺杂同型化设计，大幅降低吸收区内建电场、抑制产生复合与隧穿暗电流；通过表面等离子处理和低势能电介质钝化实现界面态控制，抑制侧边漏电。在此基础上，实现在扩散限下工作的高性能超晶格16um甚长波红外探测器，为后续发展大规模、高灵敏甚长波红外焦平面探测器奠定理论基础和技术指导。

The very long wavelength infrared (VLWIR) mainly covers the peak radiation wavelengths of room-temperature and low-temperature targets, which is very important in the application of space-based infrared technology. Particularly, with the development of information technology in weapons and equipment，the demand for low-temperature and long-range targets quickly rises in recent years, which requires urgently to extend the detection wavelength of infrared detectors to VLWIR. Many major national tasks have put forward urgent needs for high-sensitivity VLWIR focal plane arrays. However, owing to the narrower bandgap, the relatively high dark current has been the key factor that restricts the performance of VLWIR detectors. In this proposal, we aim to achieve high-performance type-II superlattice VLWIR detectors by exploring the dark current suppression. Three main strategies are involved. First, lattice-matched InAs/GaAsSb type-II superlattice with low defect density is selected to reduce the SRH recombination. Second, the barrier structure is designed and introduced by energy band tailoring, importantly in which the same doping type is adopted in both the barriers and absorption region to eliminate the built-in electric field existed in the absorption region, thus reducing the generation-recombination and tunneling current. Third, device surface treatment and passivation technology will be employed to further reduce the surface leakage current. As a result, high-performance and diffusion-limited 16-um LWIR detectors are expected to be achieved. Our work could provide theoretical guidance and technical supports for future large-format and high-performance VLWIR focal plane arrays.