累积剂量对电子器件的脉冲辐射响应影响机理研究

Ionizing irradiation can cause cumulative dose effects in electronic devices，which will render that, in the interior of the devices, the charges in the oxidizing layer and interface states grow, change the electrical performances of the devices, and severely impact the generation and transmission of the photocurrents generated by transient ionizing irradiation. Therefore, if the devices with some doses are irradiated by intensive pulsed X-ray, the functional break duration of the outputs of the devices may be evidently prolonged, and the upset threshold of the devices may remarkably decline. As a result, their radiation-resistant ability will be weakened badly, and there will be a serious deviation as their radiation-resistant ability is assessed. This phenomenon was not discovered until recent years. Many countries have realized the importance of this phenomenon, and have made a few experimental researches, but the mechanism of that has not been carefully investigated. In addition, few domestic research institutions have carried out relevant studies. Thus, in order to ascertain the mechanism that the cumulative dose effects aggravate the damage caused by the pulsed irradiation, relevant researches must be executed. This project includes the following goals and measures: the first, through the respective experiments in persistent ionizing irradiation environment and the pulsed X-ray irradiation environment, the law will be obtained that the bipolar or MOS devices with different cumulative doses respond to the pulsed X-ray irradiation; the second, the mechanism will be exposited that the cumulative dose effects impact the responses of the devices to the pulsed X-ray irradiation through theoretical researches; the third, the sensitive cells and parameters will be analyzed in the circuit level, resorting to modeling and simulation. From this work, the theoretical foundation and scientific instructions will be achieved to help to design the hardened devices and assess their radiation-resistant ability.

电离辐射在电子器件中会产生累积剂量效应，使器件内部氧化层电荷和界面态增加，造成其电学性能发生改变，严重影响器件受脉冲辐射后的光电流产生和传播。所以器件受一定累积剂量辐照后再受到脉冲射线辐照时，其扰动持续时间可能会明显增加，或者翻转阈值明显降低，抗脉冲辐射能力大幅下降。这会造成对某些关键电子系统抗辐射能力的评估出现严重偏差。此现象近些年才被发现，国际上对此给予了高度关注，并进行了相关实验研究，但机理研究很少且不深入；国内研究开展很少。因此，为认清累积剂量对器件脉冲辐射损伤的加剧机制，机理研究亟待开展。本课题通过开展累积剂量效应实验和脉冲X射线辐照效应实验，分别得到累积不同剂量后双极和MOS器件的脉冲辐射响应规律；结合器件建模、电路仿真及理论研究，阐述累积剂量对器件脉冲辐射响应的影响机制，并从电路层面分析该影响机制下的敏感单元与参数，为电子器件的抗辐射性能评估及加固设计提供理论依据和科学指导。

γ（X）射线长期低剂量率辐射和脉冲高剂量率辐射是应用在加速器实验室、空间飞行器以及库存装备中电子器件面临的一种真实恶劣环境。长期低剂量率辐照带来的累积剂量效应会使电子器件的抗脉冲辐射能力大幅降低，因此受到了国内外研究者的关注。累积剂量通过在半导体氧化层中聚集电荷，改变硅表面电势，进而影响光电流的输运和漏电流的产生，影响电子器件的脉冲辐射响应。本项目一方面以半导体单管器件为研究对象，研究了累积剂量对脉冲辐射响应的影响机制；另一方面以双极和CMOS集成电路为研究对象，获取了累积剂量对集成电路的脉冲辐射响应规律。项目提出了双极器件基区复合增强理论，阐明了累积剂量对脉冲辐射二次光电流衰减的影响机理；建立了动态闩锁模型和微分闩锁模型，阐释了体硅CMOS器件中闩锁敏感性随累积剂量的依赖关系。通过数值仿真和辐照实验，验证了理论分析和数学模型。研究成果可为电子器件的抗辐射加固和可靠性评估提供理论支持，促进我国电子器件抗辐射加固技术向深层次发展。