Research On Evaluation System Of SRAM Reinforcement Based On Interleaving

With the continuous improvement of IC's integration,the feature size is decreasing.SE(Soft Error)caused by space radiation,especially continuous MBUs(Multi-Bit Upsets)generated by neutron and other particle collision memory devices,become the main reason for the failure of space devices.The interleaving scheme proposed for continuous MBUs has become a hot research direction to improve the reliability of SRAM(Static Random Access Memory).In order to achieve the expected error correction capability,while the area and speed consumption is small,it is necessary to establish a set of evaluation model for the SRAM with different IDs(Interleaving Distance).And this kind of evaluation model is less at home and abroad,so it needs a set of evaluation system for SRAM reliability after interleaving.The mainly idea of this thesis is to establish a model that can be used to evaluate the reliability of the SRAM with interleaving combined SEC-based reinforcement.The model uses the most basic reliability parameter SER(Soft Error Rate)to measure the reliability of the SRAM after reinforcement.The evaluation system established in this paper includes the mathematical evaluation model,the software evaluation system and the hardware test platform part.The system can be used in evaluating the reliability of two kinds of processes SRAM before and after reinforcement.Three parts of the system constitute a complete evaluation system.The main work of this paper is as follows:(1)In this paper,the 0 to 500 energy segments with large neutron differential flux values in space are selected,and the proposed model is optimized.Secondly,according to the available experimental data on the cross section curve inversion process SRAM under different threshold values were fitted.On this basis,the expression of the probability of occurrence of single radiation event is deduced,and the probability of radiation event occurrence is calculated for SRAM under the two processes.Then,according to the relation of the number of flip and the energy,the probability distribution of the number of flips under different energy is proposed by using geometric and Cauchy distribution.Finally,the characteristics of the SEE(Single Event Effect)under the two processes are summarized,and the evaluation model of SRAM SER about one and two events on different interleaving distance combined with SEC is established.The mathematical evaluation model can quickly calculate the SER caused by neutrons in space under different energies.(2)Based on the proposed mathematical evaluation model,the SRAM software evaluation system is established by using VC ++ language.The system can calculate and display the cross section of SRAM,the probability of SEE caused by neutrons and the SER of SRAM after reinforcement.(3)In this paper,based on the basic concept of soft error rate,the author modify the existing hardware test platform,so that it can be used to test the actual SER of SRAM.And the SRAM soft error rate of the same interweaving distance under the two processes is compared.