【作者】 郭红霞；

【导师】 张义门； 陈雨生；

【作者基本信息】 西安电子科技大学 ， 微电子学与固体电子学， 2001， 博士

【摘要】 研究探索半导体器件电路电离辐射损伤效应和机理，提高其抗辐射水平是近年国内外微电子学领域十分重视的课题之一。抗辐射电子学已逐步成为一门综合性很强的边缘学科并发挥着愈来愈重要的作用。针对当前电离辐射效应研究的趋势及存在的不足，论文开展了电离辐射效应数值模拟计算：深入地对X射线引起的材料和器件的剂量增强效应进行了研究。主要内容有两大部分。 一、电离辐射效应数值模拟 在国内首次开展了单粒子翻转、单粒子烧毁等单粒子效应的数值模拟计算；模拟了MOSFET的单粒子翻转；力图从理论上建立分析器件SEU的可靠手段。通过输入不同粒子的线性能量传输LET(Line Energy Transfer)值，得到了已知器件结构的收集电荷与LET值的关系曲线。模拟得到的结果与电荷漏斗模型相吻合，表明了所建立的物理模型的正确性。对功率MOSFET器件单粒子烧毁(SEB)效应开展了模拟研究。理论模拟与以往的实验结果比较吻合，证明采取的物理模型的正确性。得到了SEB灵敏度与载流子浓度、基区宽度和发射结掺杂浓度等参数的变化关系。提出了改善SEB的几种加固措施。该模型对于评估器件SEB效应提供了理论模拟手段。有助于国内首次开展的微离子束单粒子效应模拟技术研究，显示了该研究在学术上和适用上的重要价值。所有这些对提高国产芯片抗单粒子辐射能力有很大意义。 开展了总剂量效应数值模拟研究。分析了总剂量辐照产生的界面陷阱的分布及性质；计算了在加电状态下NMOS、PMOS器件受辐照后的特性。结果表明，对于NMOSFET，费米能级临近导带(N沟晶体管反型)时，受主型界面态为负电荷，施主型界面态陷阱为中性，界面态陷阱将引起正的阈值电压漂移。而对PMOSFET，当费米能级临近价带(P沟晶体管反型)时，施主型界面态陷阱带正电荷，受主型界面态陷阱为中性，界面态陷阱将引起负的阈值电压漂移。模拟计算所提供的较详尽的信息深化了我们对辐照总剂量效应的认识，从而为我们利用器件模拟分析加固思想、措施的正确性，为今后研究新问题、新效应等提供了依据。 对瞬态辐照剂量率效应进行数值模拟，在国内首次采用增强光电流模型计算瞬态辐照光电流效应，该模型考虑了高注入对过剩载流子寿命的影响以及衬底电场的效应。对于高阻材料这些效应不容忽视。模型对正确预估微电路PN结瞬态电离辐射响应提供了很好的评估手段。 模拟计算了不同上升时间的快前沿电磁脉冲对PN结的毁坏效应。详细地给出了器件正常工作、失效直至烧毁的全过程。 集成电路电离辐射效应数值模拟及X射线剂量增强效应研究 二、X射线剂量增强效应研究 设计研制了多层平板电离室；首次用该电离室测量了能量为30～100keV X射线在三种材料界面附近的辐射剂量梯度分布，给出了不同材料界面剂量增强因子。实验数据与理论M。me－Carlo粒子输运方法的模拟计算结果符合很好。这说明模拟结果正确反映了不同材料界面的次级电子输运规律，其物理模型是正确的，模拟方法是可信的。 在国内首次提出材料界面的剂量增强效应与器件中同样界面出现的剂量损伤增强效应不同的观点，剂量增强因子要明显大于剂量损伤增强因子。这种概念区别既抓住物理要害，也为器件抗辐射加固提供依据。在学术上，对某些混乱的数据或提法找到了较合理的解释。并通过实验证实了这种提法的正确性。 Y、X射线电离辐射效应的等效关系研究。设计、研制了“相对测量法的双层膜”实验装置，成为研究器件X射线损伤增强效应和X、Y射线损伤等效性的有力工具。首次开展了CMOS器件4069、浮栅器件AT29C256和AT28fl56剂量增强效应研究。使用直流X光机准确测量器件的损伤增强因子。并与钻源数据进行比对，给出了CMOS器件剂量损伤增强因子。在BSgy装置上，开展了大规模集成电路浮栅器件的X射线损伤研究，给出浮栅器件y、X射线的剂量损伤等效关系。在DPF装置首次开展CMOS器件瞬态剂量率翻转增强效应研究。建立了相应的X射线剂量损伤增强效应研究方法和测试系统，为器件二射线抗辐射加固技术研究提供了实验技术支撑。更多还原

【Abstract】 Recently years, it is becoming one of the important topics to study the effects and mechanisms of ionizing radiation for semiconductor devices and integrated circuits and to improve their radiation hardening in microelectronics field. Radiation hardening electronics has been become a comprehensive marginal subject and making full use of important action. The effects of ionizing radiation are simulated and dose enhancement effects for X-ray are studied in the paper. The main contributions in this thesis are as following:Using two-dimensional numerical method, SEU for MOSFET and SEB for N channel VDMOSFET are simulated. From the theory, a reliable approach is set up for analyzing device ’s SEU. Collective charge of upset depending on LET for specific device structure is calculated for different particles LET. The results of simulation are consistent with the model of charging funnel. The effect of Single Event Burnout is investigated. The simulation results match experimental results well and are of great interest for a better understanding SEB of the occurrence of events. The effects of the minority carrier lifetime in the base, the base width and the emitter doping concentration on SEB susceptibility are verified. Some hardening solutions to SEB are provided. It is helpful to study the effects and mechanisms of Single event Phenomenon using heavy ion micro beam.Donor/Accept nature of total dose radiation-induced interface traps is analyzed. The post-irradiation behavior of the MOSFET has been simulated. It can be seen that the acceptor interface traps are negatively charged and the donor interface traps are neutral when the Fermi level is near conduction band (inversion for N-channel MOSFET), leading to a positive threshold voltage shift contribution from the interface traps. When the Fermi level is near the valence band (inversion for P-channel MOSFET), the accept interface traps are neutral, and the donor interface traps are positively charged, leading to a negative threshold voltage shift contribution from the interface traps. The model is found to be in good agreement with experimental results. An excellent evaluation approach is provided for accurately prediction of total dose radiation hardening to ionizing radiation.Transient radiation response for microcircuit PN junctions with enhancement photo current models is calculated. On the basis of Wirth-Rogers photocurrent models, the enhanced models include two additional effects such as high injection effects on excess minority carrier lifetime and electric fields in the substrate. These effects are mostpronounced in high resistively material. An excellent evaluation approach is provided for accurately prediction of transient response of modem microcircuit PN junctions to ionizing radiation. The behavior of PN junction device that is under EMP with different rapid-rise time has been simulated and analyzed. The effects such as two-dimensional current passage are given which could not be provided by one-dimensional device simulation. The whole process during which the device is under working, lapse and burnout are described in detail.A multiple parallel plate Aluminum ionization chamber has been designed for the study of dose distribution at and near the interface of different materials. Using the ionization chamber the measurements of dose gradient distribution at and near the interface of Kovar/Au1Al~ Pb/AL Ta/Al have been done for 30-lOOkeV x-rays with wide spectrum isotopic radiation accelerator and DEFs are provided. The experimental results are firstly published at home and abroad. DEF for interface of different materials is calculated by Monte-Carlo simulation of particle transportation, and the results are consistent with measured dose-enhancement factor. A reliable evaluation approach of theory is provided for studying x-ray~s dose enhancement.It has been proven that dose enhancement factors (DEF) near the different interface materials are different from dose damage enhancement factors (DDEF) near the same different int更多还原