Research Of X-Ray/Electrons Induced Single Event Soft Errors In 45 Nm SRAM

With the development of semiconductor technology,the memory becomes more and more important.Compared with other memories,Static Random Access Memory(SRAM)is widely used in information acquisition and storage due to its fast read/write speeds,low cost,and low power consumption.In complex space environment,the spacecraft is subjected to radiation damage caused by particles such as proton,neutron,heavy ion and so on,which has a serious effect on the performance of SRAM devices in the spacecraft.At the same time,with the decrease of the feature size of SRAM devices,some radiation damage that does not appear in large size is also gradually manifested.In particular,light particles,such as electrons and muons,produce electron hole pairs by ionizing or nuclear reactions,which can cause radiation damage to devices.Some studies have been carried out in this field,but the relevant researches are not thorough.In this paper,65 nm and 45 nm SRAM were used as the research object to carry out the study of the Single Event Upset(SEU)under the irradiation environment of X ray and electron accelerator.The contents include:1.The Single Event Effect(SEE)of low voltage devices was investigated by using Phillip DC X-ray machine.The experimental results show that the secondary electrons produced by the X-ray can cause upsets in the 45 nm device,but no errors on the 65 nm device.It is considered that the critical charge of 65 nm SRAM device is larger than that of 45 nm,and the secondary electrons can not deposit enough energy in its sensitive area,which can not cause 65 nm device upset.2.The geometry of the SRAM device was constructed through Geant4,and the influence of critical charge,mental interconnect overlayers and photon incidence angle on SEU is analyzed.The simulation results show that the smaller the feature size,the smaller the critical charge and the larger the cross section.Photons interaction with high Z material in the mental interconnect overlayers are generated more secondary electrons,so it is a significant increase of SEU under photoelectric effect.When the photon is inclined to the incident device,the length of the track increases,which increases the deposition energy and the upsets probability.However,when some photons are incident to the boundary of the sensitive volume,the energy of the deposition decreases,and the upsets can not be caused,which makes upsets of the vertical incident more serious than that at the oblique incidence.3.Electron induced SEU has been carried out on the electron accelerator.The experimental results show that the secondary electrons produced by the electronic nuclear reaction have a higher LET value.The secondary electron deposition energy is the main cause of the error in the device.In addition,the SEU effect of different radiation sources is found that the probability of 0 turn 1 and 1 turn 0 is the same.