Azimuthal dependence of single-event and multiple-bit upsets in SRAM devices with anisotropic layout  

作　　者：张战刚 刘杰 侯明东 孙友梅 苏弘 古松 耿超 姚会军 罗捷 段敬来 莫丹 习凯 恩云飞 

机构地区：[1]Institute of Modern Physics, Chinese Academy of Sciences [2]University of Chinese Academy of Sciences [3]Science and Technology on Reliability Physics and Application of Electronic Component Laboratory,China Electronic Product Reliability and Environmental Testing Research Institute

出　　处：《Nuclear Science and Techniques》2015年第5期69-75,共7页核技术（英文）

基　　金：Supported by National Natural Science Foundation of China(Nos.11179003,10975164,61204112 and 61204116);China Postdoctoral Science Foundation(No.2014M552170)

摘　　要：Experimental evidence is presented showing obvious azimuthal dependence of single event upsets(SEU) and multiple-bit upset(MBU) patterns in radiation hardened by design(RHBD) and MBU-sensitive static random access memories(SRAMs), due to the anisotropic device layouts. Depending on the test devices, a discrepancy from 24.5% to 50% in the SEU cross sections of dual interlock cell(DICE) SRAMs is shown between two perpendicular ion azimuths under the same tilt angle. Significant angular dependence of the SEU data in this kind of design is also observed, which does not fit the inverse-cosine law in the effective LET method. Ion trajectory-oriented MBU patterns are identified, which is also affected by the topological distribution of sensitive volumes. Due to that the sensitive volumes are periodically isolated by the BL/BLB contacts along the Y-axis direction, double-bit upsets along the X-axis become the predominant configuration under normal incidence.Predominant triple-bit upset and quadruple-bit upset patterns are the same under different ion azimuths(Lshaped and square-shaped configurations, respectively). Those results suggest that traditional RPP/IRPP model should be promoted to consider the azimuthal and angular dependence of single event effects in certain designs.During earth-based evaluation of SEE sensitivity, worst case beam direction, i.e., the worst case response, should be revealed to avoid underestimation of the on-orbit error rate.Experimental evidence is presented showing obvious azimuthal dependence of single event upsets（SEU） and multiple-bit upset（MBU） patterns in radiation hardened by design（RHBD） and MBU-sensitive static random access memories（SRAMs）, due to the anisotropic device layouts. Depending on the test devices, a discrepancy from 24.5% to 50% in the SEU cross sections of dual interlock cell（DICE） SRAMs is shown between two perpendicular ion azimuths under the same tilt angle. Significant angular dependence of the SEU data in this kind of design is also observed, which does not fit the inverse-cosine law in the effective LET method. Ion trajectory-oriented MBU patterns are identified, which is also affected by the topological distribution of sensitive volumes. Due to that the sensitive volumes are periodically isolated by the BL/BLB contacts along the Y-axis direction, double-bit upsets along the X-axis become the predominant configuration under normal incidence.Predominant triple-bit upset and quadruple-bit upset patterns are the same under different ion azimuths（Lshaped and square-shaped configurations, respectively）. Those results suggest that traditional RPP/IRPP model should be promoted to consider the azimuthal and angular dependence of single event effects in certain designs.During earth-based evaluation of SEE sensitivity, worst case beam direction, i.e., the worst case response, should be revealed to avoid underestimation of the on-orbit error rate.

关 键 词：SRAM 各向异性 方位角 单事件 翻转 静态随机存取存储器 器件 设计模式 

分 类 号：TP333[自动化与计算机技术—计算机系统结构] O343.8[自动化与计算机技术—计算机科学与技术]