重离子和脉冲激光模拟单粒子翻转阈值等效性研究

根据重离子和脉冲激发诱发单粒子翻转机理,分析了重离子和脉冲激光模拟单粒子翻转阈值（激光能量与重离子线性能量转移（LET））等效方法，得出脉冲激光与重离子单粒子翻转阈值等效计算公式。应用实验室的激光模拟单粒子效应试验系统，开展了几种器件和集成电路的单粒子翻转实验研究。利用获得的计算公式计算激光等效LET阈值，并与国内外重离子实测数据进行比较。结果表明，脉冲激光能量等效LET阈值与重离子试验LET阈值较为一致。     

34提高LET值的有效途径——高剥离态离子及0°束Q3D焦面辐照方法研究进展

我国卫星器件重离子空间辐射效应研究的发展要求器件研究的LET值越来越大,由低的LET值重离子单粒子翻转（SEU）效应研究向着更大LET值的单粒子锁定（SEL）、单粒子击穿（SEGR）、单粒子烧毁（SEB）等效应研究发展,这相应要求加速离子更重,而且能量足够大,即要求LET值能到80以上,同时,还要求离子能穿过20μm以上Si材料。解决这一问题的途径是采用高剥离态离子及0°束Q3D磁谱仪焦面辐照方法。选取高的剥离电荷态可有效提高离子的能量,Q3D磁谱仪可工作在0°下,这样一来,0°离子能量较常规方法（定角度的散射离子）能量有很大提高。     

单粒子效应辐射模拟实验研究进展

应用质子直线加速器进行了静态随机存取存储器(SRAM)的单粒子效应模拟实验研究.采用金箔散射法降低质子束流,研制了弱流质子束测量系统,测量散射后的质子束流,实验测得SRAM质子单粒子翻转截面为10-14 cm2/bit量级.利用重离子加速器和锎源进行了SRAM的单粒子效应实验.研究其单粒子翻转截面与重离子线性能量传输(LET)值的关系,得到了单粒子翻转阈值和饱和截面.实验表明252Cf源单粒子翻转截面与串列加速器的重离子单粒子翻转截面一致,说明对于SRAM,可以用252Cf源替代重离子加速器测量单粒子翻转饱和截面.与中国原子能研究院、东北微电子研究所合作开展了国内首次重离子微束单粒子效应实验.建立了大规模集成电路重离子微束单粒子效应实验方法,找到了国产SRAM的单粒子翻转敏感区.应用14MeV强流中子发生器进行了SRAM单粒子效应实验,测得了64K位至4M位SRAM器件14MeV中子单粒子翻转截面.用α源进行SRAM单粒子效应辐照实验,模拟封装材料中的232Th和238U杂质发射出的α粒子导致的单粒子翻转.测量α粒子射入SRAM导致的单粒子翻转错误数,计算单粒子翻转截面和失效率,比较三种器件的抗单粒子翻转能力,为器件的选型提供依据.并开展了路由器的α粒子辐照实验,复演了路由器在自然环境中的出错情况,为路由器的设计改进提供了依据.     

空间单粒子翻转甄别与定位系统原理样机的设计及试验

单粒子翻转（SEU）是影响空间电子设备可靠性的重要因素,本文提出了一种SEU甄别与定位技术方法,研制了原理样机。硅探测器与辐照敏感器件在垂直方向相互临近安装,粒子入射到硅探测器的位置区域与目标辐照器件单粒子翻转的物理位置相对应。采用波形数字化技术实现了多道粒子甄别与能量信号测量,通过数据回读比较法实现了SRAM器件翻转逻辑定位检测。根据实验室测试和单粒子辐照试验结果,可探测高能粒子的LET≥6?06×10-3 MeV·cm2/mg,入射粒子的位置分辨率优于5 mm,最大计数率≥10 000 s-1,SRAM器件的SEU巡检周期时间分辨率为13?76 ms。通过掌握大容量SRAM型器件的SEU甄别与定位及其辐射环境感知能力,有助于提升空间电子设备的在轨工作性能。     

总剂量和重离子协同作用下浮栅单元错误的退火特性研究

针对25 nm商用Flash存储器,利用中国科学院新疆理化技术研究所的60Coγ射线源和兰州重离子加速器先后进行了总剂量效应和单粒子效应实验。实验中器件先辐照30 krad(Si)的γ射线,然后再辐照不同线性能量转移(Linear Energy Transfer,LET)的重离子,得到了不同条件下Flash存储器浮栅单元错误的退火特性。实验结果表明与只进行重离子辐照相比,总剂量和重离子协同作用下器件浮栅单元错误消失的比例会发生变化,且在不同LET离子的辐照下表现出相异的趋势。分析认为辐照总剂量会引起浮栅单元电荷丢失和电荷俘获,影响浮栅单元的错误退火特性。     

CMOS APS光电器件单粒子效应重离子试验研究

基于新型互补金属氧化物半导体有源像素传感器(ComplementaryMetalOxideSemiconductorActive Pixel Sensor, CMOS APS)光电器件的内部结构特点,分析了重离子对CMOS APS光电器件的影响,以及CMOS APS光电器件的单粒子效应敏感性。结合CMOS APS光电器件的结构特点和辐射影响分析,形成了基于监测数据逻辑状态和图像"白点"相结合的测试方法。在此基础上,利用重离子加速器进行了单粒子效应模拟试验。试验结果表明:当重离子线性能量传输(Linear Energy Transition, LET)低于9.01 MeV·cm2·mg-1时,像素阵列没有出现扰动现象,仅是电荷在像素阵列的不断累积。同时,试验获得单粒子翻转(Single Event Upset, SEU)饱和截面对应的LET值约为42.0 MeV·cm2·mg-1。     

空间单粒子效应加速器模拟试验技术及应用

空间环境中存在大量的高能粒子，单个高能粒子穿过航天器壳体轰击到电子器件，引发器件逻辑状态翻转、功能异常等单粒子效应，进而影响航天器的可靠运行和任务达成。基于地面加速器辐照试验模拟空间单粒子效应是评估电子器件在空间应用时发生单粒子错误风险的重要手段，只有其抗单粒子效应的指标符合宇航应用要求的器件才能在航天器中使用。航天器面临的空间辐射粒子主要是重离子和质子，它们诱发的单粒子效应也最为显著。开展宇航器件单粒子效应地面模拟试验主要依托重离子加速器和质子加速器，为满足单粒子试验需求，需要研发大面积束流扩束及均匀化、高精度束流快速诊断等技术，以及满足大批量试验任务需求的高效试验终端，重点介绍中国原子能科学研究院的基于加速器的重离子单粒子效应模拟试验技术、质子单粒子效应模拟试验技术和用于器件辐射损伤敏感区识别的重离子微束技术，以及上述技术在宇航器件单粒子效应风险评估中的应用。     

利用重离子束开展半导体器件单粒子效应的探讨

讨论了利用重离子研究宇航半导体器件单粒子效应（ＳＥＥ）时应重视的几个问题，即空间辐射环境中的重离子，粒子辐射对半导体器件的影响和利用重离子束进行ＳＥＥ测试，以及重离子和质子在器件单粒子效应研究中的关系，最后介绍单粒子翻转重离子显微学。     

65nm三阱CMOS静态随机存储器多位翻转实验研究

利用4种不同线性能量转换值的重离子对一款65nm三阱CMOS静态随机存储器(SRAM)进行重离子垂直辐照实验,将多位翻转图形、位置和事件数与器件结构布局结合对器件单粒子翻转截面、单粒子事件截面及多位翻转机理进行深入分析。结果表明,单粒子事件截面大于单个存储单元内敏感结点面积,单粒子翻转截面远大于单个存储单元面积。多位翻转事件数和规模的显著增长导致单粒子翻转截面远大于单粒子事件截面,多位翻转成为SRAM单粒子翻转的主要来源。结合器件垂直阱隔离布局及横向寄生双极晶体管位置,分析得到多位翻转主要由PMOS和NMOS晶体管的双极效应引起,且NMOS晶体管的双极效应是器件发生多位翻转的主要原因。     

33 重离子微束辐照装置

采用针孔准直技术，在HI-13串列加速器上建立了微电子器件单粒子效应重离子微束辐照装置。该装置主要由5个主要部分组成：产生微束装置、定位装置、样品运动控制装置、束流注量检测装置和单粒子效应测量装置组成。图1为装置的平面布局图。     

北京G120型Q3D磁谱仪焦面探测器系统

根据HI－13串列加速器及Q3D磁谱仪的特点和物理研究课题的要求，提出了与谱仪配用的焦面探测器的重要技术性能的要求。对磁谱仪和焦面探测器的联合系统的离子鉴别方法予以较详细的讨论。提出了模型设计的参数，并估算了各种可能的贡献及最后可获得的性能及修正方法。最后给出了运行中的轻、重离子探测器的性能的实验结果。     

Recent progress in JAERI single ion hit system

Single ion hit system has been installed in heavy ion microbeam system in JAERI Takasaki for analysis of single event phenomenon in semiconductor devices. The detection and control of a single ion injection to a target have been achieved by combining a beam pulsing system with a gated detection system. The microscopic observation of a track detector hit by a single ion periodically, shows the controls of the hit positions and numbers of incident ions are successful.     

Development of a time-of-flight spectrometer at the Ruder Boškovi? Institute in Zagreb

A new TOF telescope has been constructed for thin film and surface analysis. The timing system consists of two electrostatic mirror type detectors of Busch design. The detection efficiency of timing stations for very light ions was significantly improved using DLC (diamond like carbon) foils coated with LiF instead of the conventionally used carbon foils. Ion energy is measured by a 300 mm² ULTRA ion-implanted silicon detector. For the ERDA measurements with heavy and energetic ion beams, a time-of-flight (TOF) spectrometer is positioned at 37.5°. Spectrometer can be easily moved to 120° backward angle for time-of-flight RBS analysis with low energy beam of light ions. Positioning and fine adjustments of sample orientation are performed with a motorized sample stage. The same spectrometer can be also installed at the ion microprobe scattering chamber for 3D elemental imaging.     

Experimental study on heavy ion single event effects in SOI SRAMs

Silicon-on-insulator (SOI) technologies have been developed for radiation-hardened military and space applications. The use of SOI has been motivated by the full dielectric isolation of individual transistors, which prevents latch-up. The sensitive region for charge collection in SOI technologies is much smaller than for bulk-silicon devices potentially making SOI devices much harder to single event upset (SEU). In this study, 64 kB SOI SRAMs were exposed to different heavy ions, such as Cu, Br, I, Kr. Experimental results show that the heavy ion SEU threshold linear energy transfer (LET) in the 64 kB SOI SRAMs is about 71.8 MeV cm²/mg. Accorded to the experimental results, the single event upset rate (SEUR) in space orbits were calculated and they are at the order of 10⁻¹³ upset/(day bit).     

Solar particle induced upsets in the TDRS-1 attitude control systemRAM during the October 1989 solar particle events

The three large solar particle events, beginning on October 19, 1989 and lasting approximately six days, were characterized by high fluences of solar protons and heavy ions at 1 AU. During these events, an abnormally large number of upsets (243) were observed in the random access memory of the attitude control system (ACS) control processing electronics (CPE) on-board the geosynchronous TDRS-1 (Telemetry and Data Relay Satellite). The RAR I unit affected was composed of eight Fairchild 93L422 memory chips. The Galileo spacecraft, launched on October 18, 1989 (one day prior to the solar particle events) observed the fluxes of heavy ions experienced by TDRS-1. Two solid-state detector telescopes on-board Galileo designed to measure heavy ion species and energy, were turned on during time periods within each of the three separate events. The heavy ion data have been modeled and the time history of the events reconstructed to estimate heavy ion fluences. These fluences were converted to effective LET spectra after transport through the estimated shielding distribution around the TDRS-1 ACS system. The number of single event upsets (SEU) expected was calculated by integrating the measured cross section for the Fairchild 93L422 memory chip with average effective LET spectrum. The expected number of heavy ion induced SEUs calculated was 176. GOES-7 proton data, observed during the solar particle events, were used to estimate the number of proton-induced SEUs by integrating the proton fluence spectrum incident on the memory chips, with the two-parameter Bendel cross section for proton SEUs     

亚微米特征工艺尺寸静态随机存储器单粒子效应实验研究

利用中国原子能科学研究院重离子加速器,开展了不同特征尺寸(0.35～0.13μm)CMOS工艺、不同集成度(1M、4M、8M、16M)静态随机存储器(SRAM)单粒子翻转(SEU)和单粒子闩锁(SEL)实验研究,给出了SRAM器件的SEU、SEL截面曲线。与μm级特征尺寸的器件相比,随特征尺寸的减小,单粒子翻转更加严重。测量到了令人关注的单粒子多位翻转(MBU)效应,对翻转位数进行了统计分析。MBU对目前卫星系统采用的EDAC技术提出了挑战。     

Accuracy of beam positioning in TIARA

A beam scanning and target profiling technique that provides precise and easy beam positioning on samples has been established for the light ion and heavy ion microbeam systems in TIARA of JAERI. The beam positioning accuracy in these systems was measured using nuclear track detectors, CR-39's. The beam positioning accuracy and indirect beam positioning technique in the heavy ion microbeam system enabled extremely low current microbeam to hit targeted virgin points in micro-structure semiconductor test samples for study of single event upset (SEU) transient current properties. This paper gives details of the beam scanning and target profiling system, and describes and discusses the experiments by using this system.     

On the figure of merit model for SEU rate calculations

Petersen has introduced a one parameter characterization of a device by the Figure Of Merit (FOM). It was claimed that this parameter was sufficient to estimate the SEU rate in almost all orbits. The present paper presents an analytic study of the FOM concept and compares the FOM model with other empirical models. It is found that indeed the FOM parameter gives, in most cases, a good agreement with the rates found using the full SEU cross section plots of the devices. The agreement is poorer in cases where a high portion of the proton flux comes from low energy protons and for very SEU-hard devices. This is demonstrated for certain devices (FPGAs) where the FOM predicted by proton may be smaller by an order of magnitude than the FOM from heavy ions     

Scaling of SEU mapping and cross section, and proton induced SEU atreduced supply voltage

New experimental study of heavy ion and proton induced SEU at reduced voltage (i.e. reduced critical charge) reveals interesting results. It is shown that the heavy ion cross section and microprobe mapping scale like the threshold LET and the parameter, which is almost invariant under bias changes, is the effective charge collection depth. For studying proton induced SEU and surface-barrier-detector spectra we use protons with energies from 5.6 to 300 MeV. The results are analyzed in view of the processes involved in low energy deposition by protons. Detailed calculations show the importance of straggling in proton direct ionization which might be the leading process in very sensitive devices like photodiodes