静态随机存取存储器重离子单粒子翻转效应实验研究

应用重离子加速器和 2 52 Cf源进行单粒子翻转效应实验 ,测量得到 IDT系列和 HM系列静态随机存取存储器的单粒子翻转重离子 L ET阈值为 4～ 8Me V· cm2 /mg,单粒子翻转饱和截面为 10 -7cm2 · bit-1量级 ,位单粒子翻转截面随集成度的提高而减小。实验结果表明 ,可以用 2 52 Cf源替代重离子加速器测量静态随机存取存储器的单粒子翻转饱和截面     

重离子单粒子翻转截面与γ累积剂量的关系研究

应用^252Cf源和^60Coγ源进行单粒子翻转斋与γ累积剂量的关系研究，实验结果表明，静态加电和不加电状态下，γ累积剂量对单粒子翻转截面的影响不大，无明显的规律。动态测量状态下，在存储单元中写入相同数据时，器件的单粒子翻转截面随累积剂量的增加而增大。在实验中把存储单元中的数据相反，会使器件的单粒子翻转截面水经^60Coγ源辐照时的水平，甚至更低，从而抵消了累积剂量对单粒子翻转截面的影响。     

片上存储器单粒子翻转效应诊断及修复

研究了Zynq-7000片上存储器(OCM)的单粒子翻转效应(SEU),进行了SEU的诊断设计,可以及时诊断出OCM中发生SEU的具体位置以及具体数据位,能够实现对发生于OCM中的单位翻转和多位翻转诊断;进行了SEU修复的设计,可以准确地修复OCM中发生的SEU。能够利用较少的空间资源占用和运行时间实现OCM中SEU百分之百的诊断和修复。     

基于概率统计的单粒子多单元翻转信息提取方法

航空航天电子系统对电子器件选型评估时需考虑器件的多单元翻转（MCU）情况,而MCU信息提取面临的最主要困难是缺少器件的版图信息。本文提出一种基于概率统计的单粒子MCU信息提取方法,其可在无版图信息条件下以较高精度提取单粒子翻转（SEU）实验数据中的MCU信息。该方法通过统计分析SEU实验数据中不同翻转地址间的按位异或和汉明距离以提取MCU模板,然后利用该模板提取MCU信息。采用一款位交错SRAM器件的重离子实验数据对上述方法进行了验证,结果表明,该方法能以较高的精度提取实验数据中的MCU信息。该方法可省去对器件进行逆向工程的时间和成本,提高科学研究和航空航天器件选型效率。     

加速器单粒子效应样品温度测控系统研制及实验应用

为满足国内半导体器件单粒子效应(SEE)截面与温度的关系研究需求,本文基于北京HI-13串列加速器SEE辐照实验终端研制了样品温度测控系统,实现了90~450K范围内实验样品温度的测量和控制,系统控制精度好于±1K。为验证系统可靠性,使用该系统研究了SRAM单粒子翻转(SEU)截面随温度的变化关系,在215~353 K范围内测量了SRAM翻转截面随温度的变化曲线。结果表明,SRAM SEU截面随温度的升高而增加,与理论预期结果一致。     

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。     

单粒子翻转敏感区定位的脉冲激光试验研究

利用脉冲激光单粒子翻转敏感区定位成像系统,对静态随机存储器件IDT71256开展了单粒子翻转敏感区定位的试验研究。为避开器件正面金属层对激光的阻挡,试验采用背面辐照方式进行测试。试验结果表明,存储单元中存储数据类型对器件单粒子翻转的敏感性有较大影响,由测得的单粒子翻转敏感区分布图经处理得到单粒子翻转截面,结果与重离子试验测得的翻转截面数据一致。     

SRAM型FPGA单粒子效应敏感性分析研究

首先描述了典型的SRAM型FPGA内部通常包含的三类基本资源,并分析三类基本资源内部不同功能的电路单元对单粒子效应的敏感性,归纳出Virtex系列SRAM型FPGA中6种类型的单粒子效应敏感结构单元,并得出这些敏感结构单元的单粒子翻转、单粒子功能中断、单粒子闩锁的检测方式,最后对SRAM型FPGA单粒子效应评估研究的发展趋势做了简要总结。     

深亚微米SRAM器件单粒子效应的脉冲激光辐照试验研究

利用脉冲激光模拟试验装置对IDT公司0.13 μm工艺IDT71V416S SRAM的单粒子效应进行了试验研究。在3.3 V正常工作电压下,试验测量了单粒子翻转阈值和截面、单粒子闩锁阈值和闩锁电流及其与写入数据和工作状态的关系。单粒子翻转试验研究表明,该器件对翻转极敏感,测得的翻转阈值与重离子、质子试验结果符合较好;该器件对多位翻转较敏感,其中2位翻转占绝大部分且其所占比例随辐照激光能量增加而增大,这与重离子试验结果也一致。单粒子闩锁试验分析了闩锁效应的区域性特点,发现了器件闩锁电流呈微小增大的现象,即表现出单粒子微闩锁效应,分析了这种现象对传统的抗闩锁电路设计可能造成的影响。     

模拟数字转换器AD574总剂量和单粒子翻转的协合效应

以美国亚德诺半导体技术有限公司bipolar/I2L工艺的12位模拟数字转换器AD574为研究对象,在60Coγ辐照条件下累积400 Gy(Si)的电离剂量(Total ionizing dose,TID),对累积总剂量前后的样品进行激光单粒子翻转(Single-event upset,SEU)试验,获得了0 V、1 ...     

Single Event Error Generation by 14 MeV Neutrons Reactions in Silicon

A formalism is presented which permits the calculation of electronic upsets caused by the reaction products from 14 MeV neutrons on silicon. The derivation of the formalism is developed from work in the field of radiobiology/microdosimetry. The equations follow from the mathematics of geometrical probability and are neither intuitive nor model dependent. The parameters required are the dimensions of the sensitive volume and the threshold energy for electronic upset. The results are general in the sense that any reaction, within the limits stated, can be described. Application is made to the specific case of soft error production in dynamic RAM's.     

质子和中子引起的单粒子效应及其等效关系理论模拟

根据器件几何尺寸、掺杂浓度、偏压等因素确定灵敏体积和临界电荷,从而提出单粒子效应的物理模型。考虑了质子和中子在硅中的弹性散射、非弹性散射、两体反应、多体反应以及质子的库仑散射等所有相互作用类型,采用蒙特卡罗方法模拟跟踪入射粒子与核的相互作用以及各种次级带是粒子和反冲核的能量沉积过程。采用Ziegler的拟合公式精确计算质子、a粒子、氚核、反冲核等带电离子的能量沉积。根据模拟结果确定了两种粒子引起的单粒子效应等效系数,并将模拟结果与实验数据进行了对比。     

Experimental Studies on the Self-Shielding Effect in Fissile Fuel Breeding Measurement in Thorium Oxide Pellets Irradiated with 14 MeV Neutrons

The 14 MeV neutrons produced in the D-T fusion reactions have the potential of breeding Uranium-233 fissile fuel from fertile material Thorium-232. In order to estimate the amount of U-233 produced, experiments are carried out by irradiating thorium dioxide pellets with neutrons produced from a 14 MeV neutron generator. The objective of the present work is to measure the reaction rates of 232 Th + 1 n → 233 Th → 233 Pa → 233 U in different pellet thicknesses to study the self-shielding effects and adopt a procedure for correction. An appropriate assembly consisting of high-density polyethylene is designed and fabricated to slow down the high-energy neutrons, in which Thorium pellets are irradiated. The amount of fissile fuel ( 233 U) produced is estimated by measuring the 312 keV gammas emitted by Protactinium-233 (half-life of 27 days). A calibrated High Purity Germanium (HPGe) detector is used to measure the gamma ray spectrum. The amount of 233 U produced by Th 232 (n, γ) is calculated using MCNP code. The self-shielding effect is evaluated by calculating the reaction rates for different foil thickness. MCNP calculation results are compared with the experimental values and appropriate correction factors are estimated for self-shielding of neutrons and absorption of gamma rays.     

Inelastic Scattering of 14MeV Neutrons by Heavy Nuclei

Energy spectra of neutrons scattered inelastically from natural samples of Ta, W, Au, Hg, TI, Pb and Bi have been studied at an incident energy of 14MeV, using time-of-flight technique. Angular distributions were also measured for Ta and Bi. The energy spectra from 2MeV to 4MeV were found to be qualitatively consistent with the prediction from statistical theory taking account of effects of nuclear pairing and shell structure. The Fermi gas level density parameter and the nuclear temperature were obtained by considering the contribution of the (n,2n) reaction. The variation of level density parameter plotted against mass number was found to agree with the trend predicted theoretically by Newton. Angular distributions proved to be symmetric about 90° and the spin cut-off parameter was estimated to be about 5.8 for Ta and 4.3 for Bi. Cross sections for the (n,n′2n) and (n,2n) reactions were obtained.     

14 MeV中子辐照钒引起的长寿命放射性

用HPGe探测器测量了钒以及杂质由14MeV中子活化引起的放射性,得到了50V(n,α)和51V(n,α)反应截面比值在14MeV处为0 584,并由此得到了50V(n,α)反应截面为(8 7±0 7)×10-27cm2。测量了钒中杂质成分被活化后其长寿命放射性核素的半衰期。     

Single Event Upsets in RAMs Induced by Protons at 4.2 GeV and Protons and Neutrons below 100 MeV

Several different types of random-access-memories (RAMs) have been tested for soft upset susceptibility under a variety of different particle bombardments including thermal neutrons, GeV protons, and protons and neutrons below 100 MeV and with few exceptions found to suffer single event upsets. Devices tested included 4K, 16K and 64K dynamic RAMs and 4K NMOS and 256×4 CMOS static RAMs. Mean upset fluences varied from 106 particles/cm2-upset for 64K dynamic RAMs up to no upsets observed for the 256×4 CMOS RAM. No thermal neutron induced upsets are believed to have occurred. GeV protons, simulating primary cosmic rays, caused upsets at levels of 107 particles/cm2-upset.     

Inelastic Scattering of 14MeV Neutrons by Medium Weight Nuclei

Continuous spectra of neutrons inelastically scattered from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge and As have been measured at an incident energy of 14 MeV with good statistics. Time-of-flight technique was used. In the analyses there were used three sets of inverse-reaction cross section σ_i: (1) calculated with Perey-Buck potential, (2) with Bjorklund-Fernbach potential and (3) cross section assumed to be constant. The inverse-reaction cross section does not affect appreciably the values of nuclear temperature or nuclear level density parameter for these nuclei except Ti, V and Cr. The nuclear temperature was found to be nearly constant in the mass number region of 48–75. The level density parameter as a function of mass number follows the general trend suggested by Newton. Newton's coefficient is found to be 0.092, in agreement with values obtained in other experiments. The total inelastic scattering cross sections are derived.     

脉冲激光模拟SRAM器件单粒子翻转效应的试验方法研究

针对0.13 μm和0.35 μm工艺尺寸的两款商用SRAM器件进行了脉冲激光背部单粒子翻转效应试验方法研究。单粒子翻转效应主要测试单粒子翻转阈值和单粒子翻转截面,本文主要研究了激光聚焦深度、激光脉冲注量、测试模式和芯片配置的数据对测试两者的影响。试验结果表明：只有聚焦到芯片有源区才可测得最低的翻转阈值和最大的翻转截面,此时的结果与重离子结果基本一致;注量对翻转阈值测试无影响,但注量增大时翻转截面会减小,测试时激光脉冲注量应小于1×10⁷cm^-2;测试模式和存储数据对翻转阈值和翻转截面的影响不大,测试时可不考虑。