基于中国散裂中子源的商用静态随机存取存储器中子单粒子效应实验研究

Experimental study on neutron single event effects of commercial SRAMs based on CSNS

利用中国散裂中子源反角白光中子束线开展13款商用静态随机存取存储器的中子单粒子效应实验.研究了测试图形、特征尺寸和版图工艺差异对单粒子效应的影响.结果表明测试图形对器件的单粒子翻转截面影响不大,但对部分器件的多单元翻转占比有较大的影响;特征尺寸对器件单粒子翻转截面的影响没有明显的规律,但对多单元翻转的影响规律明显,多单元翻转占比和最大位数都随着特征尺寸的降低而增大;器件版图工艺差异对器件的单粒子翻转截面和多单元翻转占比都有较大的影响.此外,通过与高原辐照实验结果对比,发现在反角白光中子源获得的多单元翻转占比小于高原辐照实验的结果,其原因是反角白光中子源实验中,中子的最高能量和高能成分占比偏小,且中子束流只有垂直入射.因此,利用反角白光中子源评估器件的大气中子单粒子效应时可能会低估多单元翻转情况.本文的结果可为研究者利用反角白光中子源开展相关研究提供参考.

The experiment of neutron single event effect was carried out at China Spallation Neutron Source(CSNS)back-n on 13 kinds of commercial SRAM.The single event upset(SEU)cross section of each device was obtained,and multiple cell upsets(MCU)were extracted from the SEUs using a statistical method without layout information.The influences of the test pattern,feature size and device layout on the SEU cross section and MCU were studied.The results show that the test pattern has little influence on the SEU cross section of the devices,but has a great influence on the MCU ratio of some devices.The feature size has influence both on the SEU cross section and the MCU ratio of the devices.The influence on SEU cross section is not definite.The influence on the MCU ratio is definite.Both the ratio and the maximum size of the MCUs increase with the decrease of the feature size.The difference of layout has great influence both on the SEU cross section and the MCU ratio of the device.In addition,compared with the results of plateau irradiation,the ratio of MCU in CSNS back-n is less than that of plateau irradiation.There are two reasons for this difference.One is that the energy spectrum of CSNS back-n is softer than that of the atmospheric neutron.The other is the neutron beam at CSNS back-n is perpendicular to the device under test.Therefore,evaluating the atmospheric neutron SEE using CSNS back-n line may underestimate the MCU ratio of the device under test.The experimental data,analytical methods and results obtained in this paper are valuable for the researchers to carry out the atmospheric neutron SEE test and the evaluation of devices on atmospheric neutron SEE.