The Study Of Single Event Effects Induced By Low-energy Protons In SRAMs Manufactured By Advanced Technologies

In this paper,a 28 nm bulk SRAM and a 28 nm fully-depleted silicon on insulator(FDSOI)SRAM are taken as research objects to explore single event effects(SEE)induced by low-energy protons.Irradiation experiments,modeling and simulation and theoretical analysis are adopted as three major research methods.The main contents and innovations of the article will be described in the following paper.(1)The background of the choosing subject and the current status of relevant technologies at home and abroad are introduced in detail.Some technological problems which could be ignored in the past gradually become challenges which need to be overcome nowadays.Mechanism study for these new emerging issues is of great significance.(2)The sensitivity of two kinds of SRAMs to low-energy protons are carefully tested through irradiation experiments by using low-energy protons and high-energy protons.It shows that the cross-section of the FDSOI SRAM is significantly lower than that of the bulk SRAM.The threat of low-energy protons is not serious enough to be unbearable,at least for the 28 nm FDSOI devices.The conclusion in this paper is inconsistent with the prediction made by previous researchers that SOI devices might be at a disadvantage when being irradiated by protons.In fact,the size of sensitive volume is still the dominant factor which has influences on the sensitivity of circuits to low-energy protons.(3)The effect of energy loss straggling on single event upsets(SEUs)induced by low-energy protons is explored and relevant mechanism is also analyzed.Irradiation experiments and Geant4 simulation are both carried out.The results show that these SEUs induced by low-energy protons should be ascribed to energy loss straggling.Linear energy transfer(LET)may not be a reliable indicator to evaluate the contribution of protons to soft error rate for modern SOI technologies.If energy loss straggling is not taken into consideration,an optimistic estimation may be obtained.Considering space is a proton-rich environment,the underestimation can bring about serious consequences.Finally,the difficulties faced by nanometer integrated circuits are reviewed and prospected.Generally speaking,the work in the present paper has a strong reference value.Especially for the study of energy loss straggling,it provides a new insight for the innovation of anti-irradiation mechanism research in the future.