Research On Micro-fabrication Process For Magnetic Random Access Memory Cells Based On TMR Effect

Magnetic random access memory MRAM (MRAM) is a non-volatile memory, Theprinciple of it is to store information by using both high and low resistance steady state ofTMR or GMR. MRAM, as a new type of data memory, has many obvious advantagescompared with other random access memory： scalability、 high speed read-writecapability、unlimited read and write endurance、Low energy consumption、high radiationresistance and the most prominent non-volatile. Its application will open a new era ofsolid-state data storage technology.The thesis focuses on the micro-fabrication process for magnetic random accessmemory cells which have a TMR effect. The article first introduces the choice of materialsof the functional layer of the magnetic random access memory cell, and then introducesthe commonly used micro-fabrication process method for the storage unit. According tothe need of the experiment of micro-fabrication of TMR, we have design a new structure.On this basis, due to the limitation of the laboratory, we design a new micro-fabricationmethod, and choose the best process after many experiments. The samples are fabricatedon micro and nano manufacturing platforms, and then we test the physical characteristicsof the samples. The result shows that each cell had a TMR effect and the magneto resistivechange rate is9%~17%, and it proves that the micro-fabrication process is successful.Finally, the author analysis the results, points out several factors which may effect TMRratio, and then discusses the prospect in future process technology of MRAM memorycells.The successful micro-fabrication process for magnetic random access memory cellsbased on TMR effect, has provided practical implementation experience for the furtherstudy the material of the MTJ、new structure of MTJ and the optimization of MRAM readand write characteristics.