Fracture of Silicon and Germanium Induced by Pulsed Electron Irradiation

This paper presents certain preliminary results on the fracture of silicon, germanium and indium antimonide resulting from pulsed electron irradiation. Experimental results show that the rapid absorption of energy can produce brittle fracture in the semiconducting materials silicon, germanium and indium antimonide. Samples were irradiated using the external electron beam from a flash X-ray generator having a peak electron energy of 2.2 Mev and a pulse width of approximately 40 nsec. All irradiations were done at room temperature with the total exposure controlled by an appropriate choice of separation distance between sample and source. Samples of various sizes and geometry were prepared from single crystals of n-type germanium and silicon. Sample orientation was obtained through X-ray diffraction. Surface treatments were varied and included a finish polish and etch. Experimental results on germanium, silicon and indium antimonide have established the fracture threshold for polished and etched bulk material to be approximately 34 cal/g for silicon, about 8.5 cal/g for germanium and 4 cal/ g in indium antimonide. Surface treatment played an important role in the observed fracture level. No dimensional dependence of the fracture threshold was observed using polished and etched bars 1 × 1 mm2 in cross section and having lengths between 1 and 25 mm. The fracture planes in both silicon and germanium were found to be the (111) crystal planes and the (110) planes in indium antimonide.     

Radiation Induced Leakage Currents in Silicon on Sapphire MOS Transistors

Measurements are reported in which photodepopulation and thermal bleaching techniques have been applied to the study of radiation induced trapped positive charge in the Al2O3 substrate of n-channel MOS/SOS devices. Photodepopulation data indicates an optical depth for the hole traps of 2.5 eV. Thermal bleaching studies yield a corresponding thermal depth of 0.75 eV. Some preliminary thermally stimulated current measurements which reveal additional low temperature stable traps are also reported.     

Transient Ionization Effects in Silicon Induced by 48 MeV Electron Pulses

Transient radiation effects induced in silicon irradiated in the temperature range 90 to 300°K by 0.007 to 4.5 microsecond pulses of 48 MeV electrons were studied using the transient response of resistivity and Hall effect voltages as the measuring probes. Results are given for one ohm-cm phosphorus-doped n-type silicon and 10 to 100 ohm-cm n-type and p-type samples. In the case of one ohmcm silicon the results clearly show the actual buildup of excess electrons produced by ionization during the time the electron pulse is irradiating the sample. Moreover, the shape of the pulse during buildup is independent of temperature as long as the electron beam pulse is kept constant. Dependence of the number of injected excess carriers on the ionization intensity (total integrated electron flux in the pulse) was found to be linear up to excess carrier concentrations of ~ 1017 cm-3. The lifetime is found to increase linearly with injection implying that the recombination may be dominated by one defect energy level. In p-type silicon the transient Hall and conductivity voltages decay in ~ 20-50 jsec. Relatively long saturation times (~ 10 to 100 microseconds) are observed in the transient Hall and conductivity voltage following an electron burst. The saturation time decreases with dose accumulation in p-type and also decreases as the irradiation temperature of the sample (both n- and p-type) is decreased. Very similar effects also are observed in n-type silicon samples.     

中国低活化马氏体钢在电子辐照下产生位错环的原位观察

高流强的中子辐照在结构材料内部产生严重的级联离位损伤,使得材料性能下降,而辐照缺陷是聚变堆材料性能下降的根本原因.为了研究结构材料在高辐照剂量下的损伤机理,针对中国低活化马氏体钢(CLAM钢),通过使用高能电子辐照来模拟中子对材料造成的高剂量辐照损伤,并对微观结构进行原位观察.进行了辐照下产生的位错环随辐照剂量的演化过程的观察,并分析了位错环浓度和尺寸随辐照剂量和温度的变化规律.     

ESD对双极型硅器件的损伤机理研究

通过理论分析,建立了双极型硅器件的ESD损伤模型,表明ESD对该类器件的损伤主要是过热失效模式.ESD电压较高时,静电放电电流引起局部过热导致PN结峰值温度达到硅的熔融温度(1 413℃)而使器件击穿烧毁;ESD电压较低时,电触点的峰值温度超过铝硅共晶的熔融温度(577℃),使器件参数退化从而发生潜在性失效.将实验结果...     

重离子辐照效应检测系统的研制

为进行静态随机存储器芯片和可编程外围接口芯片的单粒子效应研究,研发了重离子辐照效应检测系统.系统特点是人机界面友好,操作方便、直观,实现了可靠的控制与数据采集.在HI-13串列加速器上,利用此系统对静态随机存储器HM1-65642(SRAM 8K×8bit)和可编程外围接口电路ID82C55A的单粒子翻转效应和单粒子锁定效应成功地进行了试验研究,完成两种器件5种离子16O、35Cl、55Fe、79Br、127I及反冲197Au的单粒子效应的测量.     

Experiment Method of Effect for Radiation Caused by High Energy Electron Device

正In recent years,with the rapid development of space industry,the stability of the space equipment caught the attention of people.The semiconductor industry continues to scale CMOS technologies to smaller feature sizes with reduced operating voltages in pursuit of performance and density goals.Continuing decreases in device dimension     

染色体易位率和辐照剂量关系的建立及应用

采用1#2、#、4#全染色体涂染探针联用的荧光原位杂交（FISH）技术,检测60Coγ射线诱发正常人染色体稳定性畸变的易位率,建立剂量-效应关系,拟合的最佳回归方程为Y=0.0132＋0.0757D＋0.0158D2。实际应用验证结果表明,在远期受照生物剂量估算中,该剂量-效应关系有良好的应用价值和应用前景。     

Red Shift and Broadening of Backward Harmonic Radiation from Electron Oscillations Driven by Femtosecond Laser Pulse

The characteristics of backward harmonic radiation due to electron oscillations driven by a linearly polarized fs laser pulse are analysed considering a single electron model. The spectral distributions of the electron＇s backward harmonic radiation are investigated in detail for different parameters of the driver laser pulse. Higher order harmonic radiations are possible for a sufficiently intense driving laser pulse. We have shown that for a realistic pulsed photon beam, the spectrum of the radiation is red shifted as well as broadened because of changes in the longitudinal velocity of the electrons during the laser pulse. These effects are more pronounced at higher laser intensities giving rise to higher order harmonics that eventually leads to a continuous spectrum. Numerical simulations have further shown that by increasing the laser pulse width the broadening of the high harmonic radiations can be controlled.     

强流辐照对钛合金表面形貌及成分的影响

用强流脉冲离子束技术对钛合金进行了表面轰击,利用原子力显微镜(AFM)在微观尺度上对离子束诱发的表面形貌进行了分析.结果表明,在单脉冲能量密度为～1.44 J/cm2,1次辐照表面开始熔化,5次辐照,轰击表面形成密度较大的块状熔坑,高度差较原始表面增长了约200 nm.用能量色散的特征X射线谱(XEDS)分析了辐照表面...     

基于LabWindows/CVI的电子直线加速器辐照装置控制软件研发

基于分布式控制的软件设计思想,采用面向仪器与测控过程的交互式软件开发平台Lab-Windows/CVI,针对科大辐化电子直线加速器辐照装置控制系统,进行辐照装置控制软件的研究与开发。近7个月的连续运行表明该控制软件操作简便、运行稳定可靠。     

用薄靶厚衬底方法测量电子碰撞引起的K壳层电离截面

用能谱仪测量特征X射线,从而导出元素钛和钒的K壳层电离截面。为克服制靶困难,实验中采用薄靶厚衬底方法。通过电子输运计算,由厚衬底产生的反射电子对计数的影响得以修正。将结果和Green等的半经验公式以及Jessenberger等的测量数据进行了比较。     

Influence of Langmuir Turbulence on Plasma Electron Distribution During the Induced Wave Scattering

An equation is derived of the electron distribution evolution during the scattering of Langmuir waves by the plasma electrons. Calculation is performed with refraining from traditional substitution of a real plasma by a plasma probabilistic ensemble. The picture of the electron distribution evolution is compared with one suggested by Tsytovich (Refs. 12 and 19). The Tsytovich's idea of the respective electron kinetics is shown to underestimate substantially the intensity of the phenomenon and thus to evidence once more for the scientific inconsistency of the nonequilibrium statistical mechanics.Other former calculations of the particle kinetic equations are also discussed.     

Neutron Irradiation as a Means of Reducing the Incidence of Radiation Induced Breakdown in a Radiation Hard Power MOSFET

The problem of transient gamma induced "second breakdown" in a specially developed radiation hard power MOSFET is discussed, and results of experiments in which neutron irradiation was used to control minority carrier lifetime are presented. The technique is only partially successful at reducing susceptibility to second breakdown.     

淬火裂纹导致的阀门损伤研究

对裂纹损伤的阀门开展化学成分分析、扫描电子显微镜(SEM)分析、断口裂纹分析及洛氏硬度分析,得出以下结论:阀门材料的化学成分和洛氏硬度均满足设计要求,阀芯裂纹是由于材料中碳化物的大小及分布不均匀所产生的带状偏析现象造成的淬火裂纹,其现象产生于锻轧过程。     

14MeV中子辐照对发光二极管GaAsP性能的影响

发光二极管具有体积小、耗电少、调制性能好等优点,目前已广泛用于各个领域,它的辐照损伤研究曾有不少文章评论过,通过辐射损伤的研究,可以对管子的性能、辐射损伤机理及加固方法提供有价值的数据。我们利用200keV中子发生器,由T(d,n)~4He反应得到14MeV中子在室温条件下辐照发光二极管,并用光电倍加管、脉冲高度分析器测量在不同累积中子通量辐照下发光强度,从而得到发光二极管的光强变化与累积中子通量的关系,并初步确定辐射损伤常数。     

Electron Acceleration by a Focused Gaussian Laser Pulse in Vacuum

By numerically solving the relativistic equations of motion of a single electron in laser fields modeled by a Gaussian laser beam, we get the trajectory and energy of the electron. When the drifting distance is comparable to or even longer than the corresponding Rayleigh length, the evolution of the beam waist cannot be neglected. The asymmetry of intensity in acceleration and deceleration leads to the conclusion that the electron can be accelerated effectively and extracted by the longitudinM ponderomotive force. For intensities above 10^19 Wμm^2/cm^2, an electron‘s energy gain about MeV can be realized, and the energetic electron is parallel with the propagation axis.     

大破口触发的严重事故分析及缓解措施研究

采用严重事故一体化分析程序MELCOR,对国产先进压水堆核电厂进行系统建模,选取大破口触发的严重事故进行校核计算研究,获得了严重事故工况下核电厂关键参数的瞬态特性和非能动系统响应特性,并与安全分析报告中MAAP的计算结果进行了对比分析。结果表明:虽然校核计算结果与安全分析报告中的结果存在一定差异,但总体上事故序列和主要参数的变化趋势吻合良好,并且都能够在严重事故情况下保持压力容器和安全壳的完整性,放射性裂变产物释放量极低,缓解措施的设计能够有效缓解事故进程,满足核电厂的安全要求。