[论文解读] Radiation Damage in Silicon Detectors Caused by Hadronic and Electromagnetic Irradiation

E. Fretwurst, G. Lindström+2 more|ArXiv.org|Nov 28, 2002

Particle Detector Development and Performance参考文献 2被引用 5

一句话总结

本文研究了高能强子和电磁辐射对硅探测器的辐照损伤，重点提升欧洲核子研究中心大型强子对撞机（LHC）用探测器的抗辐照能力。研究结果表明，掺氧区熔硅探测器可耐受高达1 Grad的伽马射线辐照，性能衰减极小，并首次建立了探测器性能与辐照诱导点缺陷之间的1:1直接关联，为未来探测器设计中的缺陷工程提供了精确依据。

ABSTRACT

The report contains various aspects of radiation damage in silicon detectors subjected to high intensity hadron and electromagnetic irradiation. It focuses on improvements for the foreseen LHC applications, employing oxygenation of silicon wafers during detector processing (result from CERN-RD48). An updated survey on hadron induced damage is given in the first article. Several improvements are outlined especially with respect to antiannealing problems associated with detector storage during LHC maintenance periods. Open questions are outlined in the final section, among which are a full understanding of differences found between proton and neutron induced damage, process related effects changing the radiation tolerance in addition to the oxygen content and the lack of understanding the changed detector properties on the basis of damage induced point and cluster defects. In addition to float zone silicon, so far entirely used for detector fabrication,Czochralski silicon was also studied and first promising results are shown. The other three papers deal with gamma induced damage including also defects introduced either by processing steps or being inherent to the as grown silicon. However the focus is on measurements after gamma irradiation in a wide dose range. Both the changes in detector properties and defect characterisations have been studied. For the first time it is shown that in contrast to a standard process oxygenated silicon detectors withstand an irradiation dose of up to 1 Grad with only minor deterioration. Also it is shown for the first time that in this case the detector properties can directly be explained by the damage induced point defects. This 1:1 correlation is extremely promising for all future defect engineering work.

研究动机与目标

• 理解并减轻硅探测器在高强高能强子和电磁辐照下产生的辐照损伤，特别是针对大型强子对撞机（LHC）应用。
• 通过改进探测器制备工艺，缓解大型强子对撞机（LHC）维护期间的反退火效应。
• 研究掺氧及替代硅材料（如区熔法生长的硅）在提升抗辐照能力方面的作用。
• 阐明辐照诱导缺陷与探测器性能变化之间的关系，特别是对伽马射线辐照器件的影响。
• 建立点缺陷与可测量探测器退化之间的直接联系，为未来缺陷工程提供支持。

提出的方法

• 采用高剂量伽马射线和强子束对掺氧区熔硅和区熔硅晶片进行辐照实验。
• 采用缺陷表征技术（如深能级瞬态谱分析法，DLTS）识别辐照诱导的点缺陷和簇缺陷。
• 在宽剂量范围（最高达1 Grad）内，测量辐照前后探测器性能参数（如漏电流、电荷收集效率）的变化。
• 对比标准硅与掺氧硅晶片的辐照响应，评估抗辐照性能的提升效果。
• 利用定量缺陷工程模型分析缺陷浓度与探测器性能退化之间的相关性。
• 采用CERN-RD48工艺改进方案，在探测器制造过程中优化掺氧过程，提升抗辐照能力。

实验结果

研究问题

• RQ1 在制备过程中对硅晶片进行掺氧，如何影响其在强子和电磁辐照下的抗辐照能力？
• RQ2 质子与中子辐照引起的辐照损伤有何差异？其差异原因是什么？
• RQ3 除氧含量外，工艺相关因素在多大程度上影响硅探测器的抗辐照能力？
• RQ4 探测器性能退化是否可直接归因于辐照诱导的点缺陷？该相关性是否可定量预测？
• RQ5 区熔硅（传统上在高辐照探测器中使用较少）在高剂量辐照下能否达到或超过区熔硅的性能表现？

主要发现

• 掺氧区熔硅探测器表现出卓越的抗辐照能力，可耐受高达1 Grad的伽马射线辐照，性能仅出现轻微下降。
• 首次建立了辐照诱导点缺陷与探测器性能可测量退化之间的1:1直接关联，为精确缺陷工程提供了可能。
• 研究证实，掺氧显著减少了有害簇缺陷的形成，并缓解了储存期间的反退火效应，提升了探测器长期稳定性。
• 经适当掺氧处理的区熔硅在高剂量辐照环境下表现出有前途的抗辐照能力，与或优于区熔硅的性能。
• 缺陷表征结果表明，点缺陷（特别是与氧相关复合物相关的点缺陷）是探测器退化的主要贡献因素，而非簇缺陷。
• 结果表明，基于点缺陷控制的缺陷工程可作为下一代抗辐照探测器设计的可靠策略。