SRAM激光微束单粒子效应实验研究

结合器件版图,通过对2 k SRAM存储单元和外围电路进行单粒子效应激光微束辐照,获得SRAM器件的单粒子翻转敏感区域,测定了不同敏感区域单粒子翻转的激光能量阈值和等效LET阈值,并对SRAM器件的单粒子闭锁敏感度进行测试.结果表明,存储单元中截止N管漏区、截止P管漏区、对应门控管漏区是单粒子翻转的敏感区域;实验中没有测到该器件发生单粒子闭锁现象,表明采用外延工艺以及源漏接触、版图布局调整等设计对器件抗单粒子闭锁加固是十分有效的.     

低失调电压双极运放的单粒子瞬态特性研究

在Ne、Fe、Kr、Xe、Ta五种重离子入射条件下获得了运放的SET幅值-宽度分布,发现SET脉冲具有宽、窄两种形态。在SET幅值-宽度特性基础上,采用概率密度方法获得了任意SET阈值下散射截面与LET的关系。考虑入射深度与器件敏感区域的匹配,根据产生的电荷量,可对重离子-激光的SET进行关联,以便获得等效重离子的激光能量。激光与重离子的对比试验表明,选取恰当的激光能量,能够反映重离子产生的SET幅值。研究结果为双极模拟集成电路抗SET选型评估及激光试验条件的选取提供了参考。     

有机染料C22H22N4O单、双光子吸收诱导荧光的时间特性

随着高功率、超快激光技术的发展,多光子吸收诱导荧光技术已经成为研究材料的光物理特性的重要手段.由于双光子吸收比单光子吸收效率较低,很难通过实验直接测量.文中在理论上用二能级模型解释了单、双光子激发原理,推导出了单、双光子吸收诱导荧光强度与入射光脉冲强度以及脉冲作用时间的关系,研究了入射光时间分布分别为矩形、高斯型、双曲正割型时激发溶解在氯仿溶液中的C22H22N4O样品所产生的荧光峰值光强,结果表明激发光的时间分布对双光子荧光峰值强度的影响比对单光子的影响大.运用此二能级模型可以在不知道量子效率和荧光收集系数的情况下测量出单,双光子吸收截面.     

脉冲激光试验评估模拟电路单粒子效应

利用脉冲激光对典型模拟电路的单粒子效应进行了试验评估及加固技术试验验证,研究2种不同工艺的运算放大器的单粒子瞬态脉冲(SET)效应,在特定工作条件下两者SET脉冲特征规律及响应阈值分别为79.4 pJ和115.4 pJ,分析了SET脉冲产生和传播特征及对后续数字电路和电源模块系统电路的影响。针对SET效应对系统电路的危害性,设置了合理的滤波电路来完成系统电路级加固,并通过了相关故障注入试验验证,取得了较好的加固效果。     

高速PWM单粒子瞬态效应脉冲激光模拟试验研究

利用脉冲激光验证高速脉宽调制控制器（Pulse Width Modulator,PWM）单粒子瞬态效应的敏感性和防护设计。试验中,通过改变脉冲激光能量,逐步扫描PWM控制器电路,确定了诱发单粒子瞬态效应的激光能量阈值和敏感区域。通过改变PWM控制器软启动配置电路设计,验证了防护电路设计的合理性,为卫星电源子系统的单粒子瞬态效应防护设计提供技术参考。     

集成电路单粒子瞬态效应与测试方法

随着器件尺寸的等比例缩小,单粒子瞬态效应对集成电路的影响愈发明显,其产生机理及作用更加复杂。从集成电路单粒子瞬态脉冲的产生机理及模型出发,讨论分析了模拟和数字集成电路的单粒子瞬态效应,介绍了单粒子瞬态脉冲宽度的测试方法与测试结构。     

集成电路单粒子瞬态效应与测试方法

随着器件尺寸的等比例缩小,单粒子瞬态效应对集成电路的影响愈发明显,其产生机理及作用更加复杂。从集成电路单粒子瞬态脉冲的产生机理及模型出发,讨论分析了模拟和数字集成电路的单粒子瞬态效应,介绍了单粒子瞬态脉冲宽度的测试方法与测试结构。     

130 nm NMOS器件的单粒子辐射电荷共享效应

研究了同一p阱内两个130nm NMOS器件在受到重离子辐射后产生的电荷共享效应。使用TCAD仿真构造并校准了130nm NMOS管。研究了在有无p+保护环结构及不同器件间距下,处于截止态的NMOS晶体管之间的电荷共享,给出了电荷共享效应与SET脉冲电流产生的机理。同时分析了NMOS晶体管中的寄生双极管效应对反偏漏体结电荷收集的加剧作用。仿真结果表明,p+保护环可以有效地减小NMOS器件间的电荷共享,加速SET脉冲电流的泄放,证实了p+保护环对器件抗单粒子辐射的有效性,从而给出了该方法在抗单粒子辐射器件版图设计中的可行性。     

65 nm体硅工艺NMOS中单粒子多瞬态效应的研究

针对NMOS场效应晶体管由重离子辐射诱导发生的单粒子多瞬态现象,参考65 nm体硅CMOS的单粒子瞬态效应的试验数据,采用TCAD仿真手段,搭建了65 nm体硅NMOS晶体管的TCAD模型,并进一步对无加固结构、保护环结构、保护漏结构以及保护环加保护漏结构的抗单粒子瞬态效应的机理和能力进行仿真分析。结果表明,NMOS器件的源结和保护环结构的抗单粒子多瞬态效应的效果更加明显。     

双光子吸收效应与增益噪声

用微扰物理论讨论了双光子吸收效应对光纤放大器的增益噪声的影响。     

The impact of Miller and coupling effects on single event transient in logical circuits

With feature size scaling down, Miller feedback effects of gate-to-drain capacitance for transistors and coupling effects between interconnects will dramatically affect single event transient (SET) generation and propagation in combinational logic circuits. Two ways of ICs are arranged: linear and “S” types. For pulse width and delay time, SET propagations in two layouts of digital circuits are compared under considering the coupling effects between interconnects. An analytical model is used to describe the impact of Miller and coupling effects on SET propagation. A criterion for SET occurrence in digital circuits with effects of coupling and Miller feedback is presented. The influence of temperature and technology node on SET generation and propagation is analyzed. The results indicate that (1) the existence of these effects will improve the critical charge for SET generation and also reduce the estimated SER, and (2) the way of “S” type is more immune to SET than the scheme of linear.     

Cooperative two-photon effects in chalcogenide photoresists

Photosensitive chalcogenide glasses are very promising materials for pulsed holography, pulsed photolithography and pulsed optical information recording due to their exceptional sensitivity to pulsed light excitation. We present a comprehensive study of the dynamics of the pulse photoresponse of 0.3–1.0 μm thick chalcogenide glassy As₅₀Se₅₀ thin films using a transient-grating method. Both the decrease of transparency and a change of the dissolution rate were recorded after single Nd : YAG and ArF laser pulse and about (1–5)×1000 times larger energy was necessary to obtain the same changes using CW radiation. We show that when excited by a short laser pulse, two different time scales behavior and different intensity dependence of short- and long-time scale signals are present: the short-time signal behaves linearly with the input power but the long-time signal behaves quadratically with the input power. Such behavior reflects a fast electronic process followed by a slow structural rearrangement (the after-pulse effect). The obtained data indicate that the strong increase of photosensitivity following a short intense pulsed light excitation is due to a two-photon effect that aids the process of structural rearrangement as when two photons weaken or break the neighboring bonds, the probability of structural transformation increases significantly.     

Experimental study on the single event effects in pulse width modulators by laser testing

This paper presents single event effect (SEE) characteristics of UC1845AJ pulse width modulators (PWMs) by laser testing. In combination with analysis to map PWM circuitry in the microchip dies, the typical SEE response waveforms for laser pulses located in different circuit blocks of UC1845AJ are obtained and the SEE mechanisms are analyzed. The laser SEE test results show that there are some differences in the SEE mechanisms of different circuit blocks, and phase shifts or changes in the duty cycles of few output pulses are the main SEE behaviors for UC1845AJ. In addition, a new SEE behavior which manifests as changes in the duty cycles of many output pulses is revealed. This means that an SEE hardened design should be considered.     

3-D simulation study of single event effects of SiGe heterojunction bipolar transistor in extreme environment

A 3-D simulation of single event effects (SEEs) for domestic Silicon–Germanium heterojunction bipolar transistor (SiGe HBT) in extreme environment is performed with TCAD simulation tools. The influences of environment temperature and linear energy transfer (LET) on SEE are investigated. The combined effects of temperature and LET are also discussed. The results show some interesting phenomena by analyzing collected charges and transient current. The collected charges increase as temperature rises, but the current peaks decline with temperature increasing at base, collector and substrate. However, the peak of emitter transient current rises up and then declines. As LET rises, the collected charges go up linearly, and the transient current peaks also increase but their growth trends are slow. Mobility, carrier ionization and recombination of various regions at different conditions are the main causes of these differences. Current transient is very severe at low temperature. But charge collection is sensitive to high temperature and high LET. Transient pulse caused by diffusion mechanism may have a serious effect on SEEs.     

基于三维模型的InGaP/GaAs HBT单粒子效应仿真

为全面评估航天型号用元器件的抗辐射性能,对InGaP/GaAs异质结双极晶体管(Heterojunction Bipolar Transistor,HBT)的单粒子效应进行了仿真研究。首先,介绍了空间辐射环境中重离子诱发器件产生单粒子瞬态脉冲的机理。然后,建立了InGaP/GaAs HBT器件三维仿真模型,并利用蒙特卡罗方法模拟了不同能量的C、F、Cl、Br、I等重离子在器件中的射程和LET值。最后,基于ISE-TCAD仿真软件对器件的单粒子瞬态脉冲电流曲线进行了仿真和分析。结果表明:重离子在器件中产生的集电极瞬态脉冲电流可达几百微安,集电极瞬态脉冲电流与重离子的能量成反比,与离子的原子序数成正比。由此可知,InGaP/GaAs HBT器件对单粒子效应比较敏感,且对不同重离子的敏感程度不同。这可以为航天型号用元器件的设计选型和可靠性评估提供技术支撑。     

Optical and electrical effects of charges on defects in non-metals

Electrically charged defects, which are unavoidable in solids, create very strong electric fields that affect many properties of the host. In an insulator with ∿ 10 ppm charged impurities, for example, the average field strength is F ∿ 50 kV/cm. The polar lattice vibrations, which are defects of a different sort, create fields in ionic solids that are typically lO⁶V/cm at room temperature. Perhaps the most fundamental effect of these charges is the alteration of the density of electronic states. Near energy band edges this produces “band tails” that have important consequences in most electron transport properties quite apart from ordinary impurity scattering. Furthermore, the matrix elements for optical transitions among states near band edges are also affected with several significant consequences in the optical properties. Aside from these fundamental physical consequences of charged defects, a number of important practical effects occur, including the domination of semiconductor laser properties, limitation of light transmission in quartz fibers and behavior of amorphous semi-conductors.     

Analysis and RHBD technique of single event transients in PLLs

Single-event transient susceptibility of phase-locked loops has been investigated. The charge pump is the most sensitive component of the PLL to SET, and it is hard to mitigate this effect at the transistor level. A test circuit was designed on a 65 nm process using a new system-level radiation-hardening-by-design technique. Heavy-ion testing was used to evaluate the radiation hardness. Analyses and discussion of the feasibility of this method are also presented.     

Modeling single event crosstalk speedup in nanometer technologies

With advances in CMOS technology, circuits become increasingly more sensitive to transient pulses caused by single event (SE) particles. In addition, coupling effects among interconnects can cause SE transients to spread electronically unrelated circuit paths which may increase the SE Susceptibility of CMOS circuits. The coupling effects among interconnects need to be considered in single event modeling and analysis of CMOS logic gates due to technology scaling effects that increase both SE vulnerability and crosstalk effects. This work reports on the signal speedup effects caused by SE crosstalk and then proposes a best-case delay estimation methodology for use in design automation tools for the first time to our knowledge. The SE coupling speedup expressions derived show very good results in comparison to HSPICE results. Results show an average error of about 8.42% for best-case delay while allowing for very fast analysis in comparison to HSPICE.