摘要：重离子实验结果表明,具有高线性能量转移(LET)或大角度入射的快重离子导致静态随机存储器(SRAM)中的多位翻转(MBU)比例增大,甚至超过单位翻转比例。单个离子径迹中的电荷可以沿着径向扩散数个微米,被临近的灵敏区收集后引起MBU。器件灵敏区的各向异性空间布局与离子入射方向共同影响测试器件的MBU图形特征。位线接触点的纵向隔离导致横向型成为主要的两位翻转图形;"L"型和"田"型分别是主要的三位翻转和四位翻转图形。最后,对SRAM抗MBU加固设计和实验验证方法进行了讨论。

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 *** 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 *** 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.