新型微电子技术单粒子效应研究面临的挑战

随着器件特征尺寸的减小,单粒子效应成为影响CMOS工艺空间辐射环境可靠性的关键因素之一。未来航天和国防系统需要了解新型工艺中的单粒子效应损伤机制及其加固方法,包括在器件几何尺寸和材料方面的改变如何影响到能量淀积、电荷收集、电路翻转、参数退化等等。分析了随着特征尺寸减小,在高速数字电路中的单粒子瞬态效应SET的影响,包括由质子的直接电离作用产生的单粒子效应、粒子能量效应和非直接电离对单粒子效应的影响。对可能替代体硅器件的新型器件单粒子能力进行了简要介绍。     

CMOS图像传感器单粒子效应及加固技术研究进展

互补金属氧化物半导体(Complementary Metal Oxide Semiconductor,CMOS)图像传感器(CMOS Image Sensor,CIS)在空间应用时会受到单个粒子辐照影响,这通常会导致CIS采集图像出现异常,严重时会导致器件功能失效。本文从不同粒子的角度:重离子、质子、电子和中子,从CIS容易发生的单粒子效应类型:单粒子瞬态(Single Event Transient,SET)、单粒子翻转(Single Event Upset,SEU)、单粒子闩锁(Single Event Latchup,SEL)、单粒子功能中断(Single Event Functional Interrupt,SEFI)等方面综述了CIS单粒子效应研究进展。简要介绍了CIS单粒子效应加固技术研究进展。分析总结了目前CIS单粒子效应及加固技术中亟待解决的问题,为今后深入开展相关研究提供理论参考。     

卫星有效载荷开关电源单粒子瞬态效应的防护研究

本文分析了脉宽调制器（PWM）中单粒子瞬态效应的产生过程、传播机制以及对开关电源的影响,结合卫星有效载荷专用电源的技术特点,提出了一种有效的防护策略。脉冲激光及重离子试验方法均验证了机理分析的正确性和改进措施的有效性。为扫除这类器件在太空应用的重要隐患提供了新的思路。     

CCD电离辐射效应损伤机理分析

研究了CCD电离辐射引起总剂量效应和瞬态电离效应的损伤机理.分析了总剂量效应导致OCD平带电压和阈值电压漂移、表面暗电流密度增大以及饱和输出电压下降的规律和机理.研究了单粒子瞬态电离辐射导致OCD单粒子瞬态电荷产生的机理,研究了瞬态脉冲电离辐射导致OCD信号电荷损失的机理.     

单粒子瞬态电流脉冲测试技术研究进展

单粒子瞬态（single-eventtransient,SET）电流脉冲测试技术是在重离子微束中非常重要的一种实验测试技术手段,可以用来测量束流入射位置与单粒子瞬态电流脉冲之间关系,给出电流瞬态脉冲参数（如上升时问、衰退时问以及峰高等）的二维分布图,在微米空间尺度和皮秒时间尺度上对电荷产生、传输以及收集的瞬态过程进行研究。     

Flash型FPGA的单粒子效应测试系统研制

研制了一套Flash型FPGA的单粒子效应测试系统,其具有片上SRAM/Flash ROM单粒子翻转效应测试、D触发器单粒子效应测试、锁相环与时钟网络单粒子瞬态效应测试、单粒子瞬态脉冲宽度测试等功能。本文介绍了该系统的测试原理和软硬件实现方法。     

脉冲激光背照射单粒子效应实验研究

为避免集成电路正面金属层对激光的阻挡,采用背面照射的方法对非加固SRAMIL-2和加固SRAM1020-2进行了单粒子效应实验。对脉冲激光背面照射实验的相关问题进行了探讨。比较了两种器件产生单个位翻转的有效激光阈值能量,验证了器件加固措施的有效性。     

JFET区宽度对SiC MOSFET单粒子效应的影响

SiC MOSFET(金属-氧化物半导体场效应晶体管)关键参数——结型场效应晶体管(JFET)区宽度一直被认为是SiC MOSFET单粒子效应的主要影响因素。针对这一影响因素,以同一结构不同JFET区宽度的1.2 kV SiC MOSFET器件为对象进行单粒子效应实验,探究JFET区宽度对器件单粒子烧毁阈值电压、漏电退化阈值电压以及负栅压条件下器件性能的影响。结果表明：随着JFET区宽度的减小,漏电退化阈值电压增大;减小器件JFET区宽度可有效改善器件的抗单粒子效应能力;在负栅压条件下对器件单粒子效应也会有此效果。采用Sentaurus TCAD进行模拟仿真,模拟结果证实,JFET区宽度以及负栅压的变化会影响氧化层下JFET区内空穴的积累,随之影响氧化层电场强度,从而影响器件单粒子漏电退化,与实验结果相符。以上结果为SiC MOSFET抗单粒子效应加固提供了理论基础。     

光电耦合器的单粒子瞬态脉冲效应研究

利用脉冲激光模拟单粒子效应实验装置研究光电耦合器HCPL-5231和HP6N134的单粒子瞬态脉冲(SET)效应.实验获得了相关器件的单粒子瞬态脉冲波形参数与等效LET的关系,并甄别出器件SET效应的敏感位置,初步分析了SET效应产生的机理.利用脉冲激光测试了光电耦合器的SET宽度与等效LET的关系,并尝试测试了两种光电耦合器的SET效应的截面,其中,HCPL-5231的实验结果与其他文献利用重离子加速器得到的数据符合较好,验证了脉冲激光测试器件单粒子效应的有效性.     

锁相环单粒子瞬态效应的电路级仿真

对130 nm工艺电荷泵锁相环(PLL,phase-locked loop)开展单粒子瞬态(SET,single event transient)的电路级仿真,根据输出端信号的最大错误脉冲和最大相移寻找SET最敏感节点.结果表明,电荷泵输出级的晶体管对SET最敏感.介绍了一种加固方法,电荷泵PLL加固前后的抗SET性能...     

光电耦合器4N49单粒子瞬态脉冲效应的试验研究

通过脉冲激光模拟单粒子效应,对光电耦合器4N49的单粒子瞬态脉冲（SET）效应进行了试验研究。在10V工作电压下,获取了4N49在特定线性能量传输（LET）值下的SET波形特征及其变化规律,得到了器件SET效应的等效LET阈值为10MeV•cm²•mg^-1,而饱和截面数值则高达1.2×10^-3cm²。试验验证了4N49的SET效应对后续数字电路的影响状况,定量研究了SET效应减缓电路的有效性,通过设计合理的电路参数可将器件在5V工作电压下的SET效应阈值由7.89MeV•cm²•mg^-1提高至22.19MeV•cm²•mg^-1。4N49的SET效应试验研究为光电耦合器SET效应的测试及防护措施的有效性验证提供了新的试验方法。     

Analysis of single-event transient sensitivity in fully depleted silicon-on-insulator MOSFETs

Based on 3 D-TCAD simulations, single-event transient(SET) effects and charge collection mechanisms in fully depleted silicon-on-insulator(FDSOI) transistors are investigated. This work presents a comparison between28-nm technology and 0.2-lm technology to analyze the impact of strike location on SET sensitivity in FDSOI devices. Simulation results show that the most SET-sensitive region in FDSOI transistors is the drain region near the gate. An in-depth analysis shows that the bipolar amplification effect in FDSOI devices is dependent on the strike locations. In addition, when the drain contact is moved toward the drain direction, the most sensitive region drifts toward the drain and collects more charge. This provides theoretical guidance for SET hardening.     

变温辐照对双极电压比较器LM2903在不同偏置状态下的单粒子瞬态影响

利用变温辐照方法模拟了低剂量率辐照,研究了双极电压比较器LM2903的电离总剂量（TID）-单粒子瞬态（SET）的协同效应。结果表明,高电平工作状态偏置时,TID对LM2903的SET具有抑制作用;低电平工作状态偏置时,TID对LM2903的SET具有促进作用。电离辐照诱发的界面态缺陷电荷是TID-SET协同效应产生的根本原因,电压比较器的输出级结构导致了偏置状态对TID-SET协同效应的不同影响。     

基于二维查找表的SET耦合注入方法

随着器件特征尺寸的减小,利用独立电流源进行单粒子瞬态（SingleEventTransient,SET）注入的方法与实际脉冲存在很大误差,器件/电路混合模拟能与实际较好符合,但在大规模组合逻辑的软错误率分析中使用器件/电路混合模拟非常耗时,急需电路级快速的SET注入方法。针对0.18μmCMOS反相器构建了基于二维查找表的SET耦合注入方法,并与器件/电路混合模拟的结果进行比较。结果发现：基于二维查找表的SET耦合注入方法与器件/电路混合模拟方法的结果比较符合,而仿真速度比器件/电路混合模拟快3个数量级。     

14 nm FinFET器件单粒子瞬态特性研究

为评估鳍式场效应晶体管（FinFET）的本征抗辐射能力,本文通过三维工艺计算机辅助设计（TCAD）仿真研究了14 nm FinFET工艺的单粒子瞬态（SET）特性。研究结果表明,在不同的线性能量传输（LET）值及不同的入射位置下,FinFET器件具有不同的单粒子敏感性。SET脉冲宽度随LET值的增大而展宽。此外,SET特性与粒子轰击位置的关系呈现出复杂性。对于低LET值（LET≤1 MeV·cm2/mg）,SET特性与重离子的入射位置具有很强的依赖性;对于高LET值（LET＞10 MeV·cm2/mg）,由于加强了衬底的电荷收集,SET特性与粒子轰击位置的依赖性减弱。     

Synergistic effect of enhanced low-dose-rate sensitivity and single event transient in bipolar voltage comparator LM139

The bipolar voltage comparator LM139 were exposed to ionizing radiation with a high-dose-rate of 10 rad(Si)/s and a low-dose-rate of 0.01 rad(Si)/s; then, pulsed laser single-event-transient (SET) testing was performed. The experimental results show that the SET phenomenon of LM139 after low-dose-rate irradiation of 0.01 rad(Si)/s is obviously different from the SET phenomenon of LM139 after high-dose-rate irradiation of 10 rad(Si)/s. After irradiation with the low-dose-rate, the comparator LM139 has Enhanced Low Dose Rate Sensitivity (ELDRS) in terms of the total dose effect, and the SET was further influenced by ELDRS. The greater gain degradation of the internal transistor in LM139 with low-dose-rate irradiation is the direct cause of this phenomenon.     

A cycle configuration for large-scale helium refrigerator for fusion devices towards complete mitigation of the effects of pulsed heat load

Large-scale helium refrigerators in fusion devices work in pulsed heat load condition. The immediate effect of pulsed heat load is mass flow rate fluctuation at the low pressure return stream to the cold-box of the refrigerator. As a result, thermodynamic properties of all the intermediate state points of the cold-box vary widely and may go beyond operating limits. Therefore, for continuous operation, the refrigerators need modification in cycle configuration in order to mitigate the effects of pulsed heat load generated out of the operation of the fusion devices. A number of mitigation techniques exist and none of them is capable of mitigating the mass flow rate fluctuation completely. However, combinations of two or more methods have been found to be effective in mitigation of the effects of pulsed load to the maximum possible extent. In this paper, a cold-end configuration has been proposed that is constituted of combination of different mitigation schemes proposed in previous works. Dynamic simulations are performed to predict the performance of the modified cycle configuration and for validation of the concept towards achievement of complete mitigation. Results of the work have revealed that through the proposed cold-end configuration, almost complete mitigation can be obtained.     

Efficacy assessment of independent severe accident mitigation measures in OPR1000 using MELCOR code

In-vessel and ex-vessel mitigation strategies have been revisited to improve the severe accident management (SAM) for operating nuclear power plants. Because independent mitigation measures tend to produce positive and adverse effects simultaneously, it is necessary to investigate the efficacy of individual measures by means of proper quantification. Thus, in the present study we investigated the overall efficacy of existing SA mitigation strategies prepared for the Optimized Power Reactor 1000 MWe (OPR1000) by means of MELCOR 1.8.6 code. The numerical evaluation showed that the Mitigation-01, feeding water into the steam generators, is the most effective among the other mitigations. In addition, Mitigation-02, reactor coolant system depressurization, could not mitigate the SA sufficiently when applied individually. Among the four ex-vessel mitigation strategies, execution of containment spray was effective in removing most of the aerosol fission product but also intensified hydrogen combustion by increasing the partial hydrogen pressure owing to steam condensation. Mitigation-07, operation of passive autocatalytic recombiners (PARs), could reduce the hydrogen concentration, though the catalytic reaction was predicted to increase the containment pressure. In conclusion, this study suggests that mitigation measures should be carefully selected, and that counteracting measures should be prepared to minimize potential adverse effects.     

ATWS缓解系统可靠性分析

未能紧急停堆的预期瞬态（ATWS）缓解系统是保证中国先进研究堆（CARR）安全的重要系统之一。当发生预期运行瞬态,反应堆未能紧急停堆时,通过ATWS缓解系统动作实现停堆,从而保护反应堆安全。ATWS缓解系统的高可靠性是保证其完成预期功能的重要条件,因此对该系统的可靠性给予了高度重视。本文以ATWS缓解系统为研究对象,利用故障模式及影响分析和故障树等可靠性分析方法,建立相应模型,对ATWS缓解系统进行了定性和定量的分析,得到了ATWS缓解系统发生故障的概率和最小割集,找出了薄弱环节,提出了改进措施和建议,其可靠性水平已达到CARR工程的设计要求,验证了设计,为CARR其他系统分析和验证奠定了基础。     

Comparison of D-flip-flops and D-latches:influence on SET susceptibility of the clock distribution network

As technology scales down, clock distribution networks(CDNs) in integrated circuits(ICs) are becoming increasingly sensitive to single-event transients(SETs).The SET occurring in the CDN can even lead to failure of the entire circuit system. Understanding the factors that influence the SET sensitivity of the CDN is crucial to achieving radiation hardening of the CDN and realizing the design of highly reliable ICs. In this paper, the influences of different sequential elements(D-flip-flops and D-latches, the two most commonly used sequential elements in modern synchronous digital systems) on the SET susceptibility of the CDN were quantitatively studied. Electrical simulation and heavy ion experiment results reveal that the CDN-SET-induced incorrect latching is much more likely to occur in DFF and DFF-based designs. This can supply guidelines for the design of IC with high reliability.