Researches On Radiation Effects And Radiation-Hardening Of Resistive Random Access Memory

The particularity of space environment put forward high requirements for the radiation tolerance of the aerospace electronic equipment.Non-volatile memory,as the core component for data and program storage of the aerospace electronic system,must have a certain degree of anti-radiation ability to meet the performance requirements of the space application.Resistive random access memory(RRAM)is considered as one of the most promising candidates for next generation of non-volatile memory.Besides the advantages such as high operation speed,high storage density,low power consumption,simple structure,compatible with the CMOS process,etc,conductive filament-based switching mechanism also allow them to exhibit a natural radiation-hard superiority to FLASH.Based on this,this thesis focuses on the study of the radiation effects and radiation-hardening techniques of RRAM.Firstly,the radiation effects in the space environment are introduced,the production mechanism and the influence on semiconductor devices are discussed.Then,the working mechanism of RRAM is introduced from the aspects of fabrication process,structure,material,working mode and so on.In order to study the radiation response of RRAM,the radiation effects of independent 1Mb RRAM chip is investigated.A RRAM test system is implemented on FPGA board for the irradiation test.The radiation experiments are performed on the ground to simulate the space radiation-induced total ionizing dose(TID)effect and single event effect(SEE).TID effect can lead to a dramatically increase in leakage current in the access NMOS transistor of 1T1R storage cell structure that results in read decision failures,thus part of logic 0 are decided to be logic 1,which was observed during TID testing.A simulation verification on the practical read circuit of 1Mb RRAM by HSPICE is performed.SEL(single event latch up)was observed in the peripheral circuits of RRAM during the pulsed laser irradiation,while the storage array kept stable after irradiation by heavy ions.Both the experimental results show that the RRAM memory cell has a strong resistance to extremely high levels of radiation.However,the peripheral CMOS circuits of RRAM and the selected NMOS transistor are sensitive to radiation,which may lead to the degradation of the chip function and performance.Finally,according to the failure mechanism,the radiation-hard techniques are discussed.The radiation tolerance of the 1Mb RRAM chip can be improved by purely focusing on the peripheral CMOS circuits and the selected NMOS transistors,through the implementation of radiation-hardness-by-design(RHBD)or radiation-hardness-by-process methods.Lay the foundation for the next research.