甲基苯基乙烯基硅橡胶电离总剂量效应

甲基苯基乙烯硅橡胶具有耐高低温、防震等独特优势,在航天器的减震、密封等领域具有广泛应用前景。研究了甲基苯基乙烯基硅橡胶的电离总剂量效应。结果表明,随着辐射剂量的增加,甲基苯基乙烯基硅橡胶的力学性能出现了不同程度的退化。拉伸强度和撕裂强度变化规律以1×106 Gy(Si)剂量点为分界点。低于该剂量,拉伸和撕裂随剂量增加快速下降;高于该剂量时,随辐照剂量增加,拉伸强度出现一定程度反弹,呈现出宽"U"形,而撕裂强度则是先增加后下降。拉断伸长率和邵氏硬度A随辐照剂量增加分别出现快速下降和增加,最终接近饱和。最后,从辐射交联和裂解方面讨论了甲基苯基乙烯基硅橡胶电离总剂量效应的潜在物理机制。     

ELDRS and dose-rate dependence of vertical NPN transistor

The enhanced low-dose-rate sensitivity (ELDRS) and dose-rate dependence of vertical NPN transistors are investigated in this article. The results show that the vertical NPN transistors exhibit more degradation at low dose rate, and that this degradation is attributed to the increase on base current. The oxide trapped positive charge near the SiO₂-Si interface and interface traps at the interface can contribute to the increase on base current and the two-stage hydrogen mechanism associated with space charge effect can well explain the experimental results.     

不同发射极面积npn晶体管高低剂量率辐射损伤特性

影响npn晶体管辐射损伤的因素有很多,如晶体管工艺、剂量率以及辐照偏置等.主要研究了三种发射极面积的国产npn晶体管在高低剂量率下的辐射损伤特性,分析了发射极尺寸对辐射损伤的影响.研究结果表明,国产npn晶体管具有低剂量率损伤增强效应,且发现当小电流注入下晶体管的辐射损伤会表现得愈加显著.比较三种发射极尺寸的晶体管辐照响应发现,发射极周长面积比P/A越大时晶体管归一化过剩基极电流ΔI_B/I_B0也越大.详细阐述了npn晶体管辐射损伤机制,从发射极尺寸和晶体管工作电压角度对npn晶体管的加固保证方法进行了探索. 关键词： 发射极面积 国产npn晶体管 剂量率 辐射损伤     

电子元器件屏蔽封装材料的屏蔽效果

针对电子元器件屏蔽封装材料的屏蔽效果评估方法及理论计算在器件屏蔽封装中应用的问题,本文通过理论计算一种屏蔽材料对1.0MeV电子的屏蔽效果,以及对应的实验验证,指出此种屏蔽材料有很好的屏蔽电子辐射作用.研究证明了理论与实验相互验证的方法能很好的评估屏蔽材料的屏蔽效果,同时指出理论计算的结果能在屏蔽材料设计中作为依据.     

Effects of orientation of substrate on the enhanced low-dose-rate sensitivity （ELDRS） in NPN transistors

The radiation effects and annealing characteristics of two types of domestic NPN bipolar junction transistors, fabricated with different orientations, were investigated under different dose-rate irradiation. The experimental results show that both types of the NPN transistors exhibit remarkable Enhanced Low-Dose-Rate Sensitivity (ELDRS). After irradiation at high or low dose rate, the excess base current of NPN transistors obviously increased, and the current gain would degrade rapidly. Moreover, the decrease of collector current was also observed. The NPN transistor with <111> orientation was more sensitive to ionizing radiation than that with <100> orientation. The underlying mechanisms of various experimental phenomena are discussed in detail in this paper.