高能粒子辐照下碳化硅功率器件退化机理研究

With the rapid development of China's space industry, in order to improve performance and reduce weight, the high-voltage power device with low power consumption manufactured by the silicon carbide (SiC), the third-generation semiconductor material, is strongly needed by the new generation of high-capacity communications satellites, deep space explorers and other spacecraft. In the space radiation environment, high-voltage SiC power devices are exposed to risks of performance degradation or even failure caused by irradiation of high-energy particles. The degradation mechanism caused by the high-energy particles on SiC power device has not been understood. The study of radiation effect and evaluation method is a hot topic in the world. Based on the research status in this field and the existing foundation of the project group, this study takes the high-voltage SiC power devices as samples and focuses on exploring the performance degradation and effect mechanism of SiC high-voltage power device, which are caused by the irradiation of high-energy particles. In combination with simulation, advanced physical analysis methods are adopted to establish a physical analytical model of effect mechanism. The influence of test conditions such as incident particle, temperature and voltage on the single-particle effect of SiC power device is further studied, and a guideline for the evaluation method of single-particle effect on SiC power device is proposed. The study is to provide key technological support for the application of SiC power devices in the new generation spacecraft in China, which is of vital significance to satisfy the demands of rapid development for the spacecraft, to promote the development of home-made hardened SiC power devices.

我国航天事业飞速发展，为了提高性能、降低重量，新一代大容量通信卫星和深空探测等航天器迫切需要使用由第三代半导体材料碳化硅（SiC）制造的高压、低功耗的新型功率器件。目前对SiC高压功率器件高能粒子辐照引起性能退化机理认识不足，影响了其在新一代航天器中应用。新型SiC高压功率器件高能粒子辐照引起的退化机理是当今国际研究热点。本课题以SiC高压功率器件为对象，结合目前该领域研究现状和项目组已有的基础，重点研究高能粒子在SiC器件内部辐射损伤产生机制及其影响机理，采用先进的物理分析手段，结合模拟仿真，研究建立效应机制物理解析模型。进一步研究入射离子、温度和电压等试验条件对SiC功率器件单粒子效应的影响，提出SiC 功率器件单粒子效应评估方法指南。本课题将为我国新一代航天器应用SiC功率器件提供重要技术支撑，对推动我国新一代航天器快速发展、促进国产加固SiC功率器件的发展有重要意义。

我国新一代航天器研制，对碳化硅（SiC）高压功率器件提出了迫切应用需求。SiC高压功率器件空间应用面临辐射效应问题。SiC高压功率器件高能粒子辐照引起退化机理是当今国际研究热点。本课题以代表性的SiC器件为样品，用重离子、质子和反应堆中子等进行了辐照试验，研究了高能粒子在SiC器件内部的辐射损伤产生机制及其影响机理，验证了SiC器件单粒子效应存在三个区：无损伤区、参数退化区、烧毁失效区。研究得出SiC器件单粒子效应与入射离子LET、注量、偏置电压等因素有关，首先，SiC器件单粒子效应敏感性与偏置电压严重相关，随偏压增加，单粒子损伤阈值降低；辐照引起的漏电流具有累积效应，随入射注量增加漏电流增加；随着温度提高，单粒子烧毁阈值电压增加；利用DLTS对辐照后SiC功率器件进行缺陷分析。测试发现DLTS信号（ΔC/C）主要呈现出三个峰，依次将其命名为E0.4、Z1/Z2和EH。辐照后，E0.4能级和Z1/Z2能级基本未发生变化，EH能级有展宽的现象。E0.4和Z1/Z2通常认为是具有特定结构的硅空位和碳空位。分析认为，EH缺陷的复杂程度与漏电流的退化成正相关。推断这些靠近SiC外延层表面的复杂缺陷是导致SiC二极管漏电退化的原因之一。试验研究得出高能质子会引起SiC器件单粒子烧毁，SiC器件位移损伤不敏感。研究发现重离子辐照会在器件内部产生潜在损伤，SiC器件单粒子试验方法中应增加辐照后可靠性考核试验流程，评估潜在损伤对可靠性的影响。部分研究成果已为国产SiC器件加固和宇航选用提供支持。