55 nm工艺静态随机存储器的软错误率预测

Method for Predicting Soft Error Rate of 55nm SRAMs

针对重离子诱导的55nm工艺静态随机存储器中的单粒子翻转现象,采用Geant4蒙特卡洛仿真方法对其软错误率展开研究与预测。仿真采用不同种类和能量的重离子,评估SRAM的翻转截面及多单元翻转的概率。通过分析不同能量、不同入射角度的重离子轰击所诱导的单粒子单个单元翻转与多单元翻转的比例,推导出粒子入射角度对翻转发生概率的影响规律。特别针对空间环境中的宇宙射线模型,建立一种对粒子辐射影响下的55nm工艺SRAM的软错误率的预测方法。通过与辐照试验的结果对比,证明经过校准的嵌套敏感体模型能够更准确地评估SRAM的翻转截面。

Aiming at the phenomenon of Single Event Upset induced by heavy ions in SRAM of 55nm process,the soft error rate is studied and predicted by Geant4 Monte Carlo simulation method.The simu-lation uses different kinds and energies of heavy ions to evaluate SEU cross section of SRAM and the pro-bability of Multiple Cell Upset.By analyzing the ratio of single particle Single Cell Upset to MCU induced by heavy ion bombardment with different energy and different incident angles,the influence law of particle incident angle on SEU probability is deduced.Especially for the cosmic ray model in space environment,a prediction method of soft error rate of 55nm SRAM under the influence of particle radiation is established.Compared with the results of irradiation test,it is proved that the calibrated nested sensitive body model can evaluate the SEU cross section of SRAM more accurately.