Geant4模拟δ电子对单粒子翻转的影响

Impact of Delta-electrons on Single-event Upsets with Geant4 Simulation

利用Geant4蒙特卡洛程序包,基于RPP(Rectangular ParallelePiped Volume)模型构建SRAM器件单元的灵敏体积,编写了重离子在器件材料中的输运程序和单粒子翻转截面计算方法,得到了简化器件结构的单粒子翻转截面σ与线性能量转移LET的关系曲线,计算得到的翻转LET阈值和饱和截面与实验结果基本一致。模拟获得了LET值为99.69MeV/(cm-2.mg)的Bi离子及LET值为69MeV/(cm-2.mg)的Bi离子和Xe离子在器件材料中产生的δ电子分布图像,讨论了δ电子分布对翻转截面的影响。计算了灵敏体积中能量沉积与δ电子分布的关系,认为δ电子分布对单粒子效应的影响随着器件的特征尺寸减小将更加严重。

In this paper,the sensitive volume of SRAMs was constructed based on RPP(Rectangular ParallelePiped Volume) model using the Monte-Carlo code Geant4.The interactions of heavy ion with materials and the SEU(Single Event Upset) cross section calculation method were presented in the program.The SEU cross-section curves with the linear energy deposition ware obtained.The SEU threshold value and saturation cross section were consistent with the testing data with heavy ions beam.The δ-electrons distribution were different in the device material,which were generated by Bi ion with LETs of 99.67 MeV/(cm-2·mg) and Bi ion,Xe ion with LETs of 69 MeV/(cm-2·mg).These results indicate δ-electrons distribution impacts on the SEU cross section.According to the relation of energy deposition in the sensitive volume,the δ-electrons distribution have more and more important effect on the Single Event Effect with reducing the feature size of semiconductor devices.