Study On The Properties Of Phase-change Memory Device With GeTe/Sb2Te3 Superlattice Structure Under An External Magnetic Field

PCRAM is considered to be one of the most promising next-generation non-volatile memory for replacing dynamic random access memory?DRAM?,and it has the characteristics of fast storage speed?high reliability and long service life.As one of PCRAM,superlattice phase change memory is received widespread attention and research with its unique structural and physical characteristics.GeTe/Sb₂Te₃ is a nonmagnetic superlattice films,and the study found the change of threshold voltage with this structure under external magnetic field,and the resistance under external magnetic field is much higher than the resistance without an external magnetic field in a certain range of write voltage,this phenomenon of GeTe/Sb₂Te₃ superlattice is called magnetoresistance effect.In this paper,we mainly studied the influence of superlattice PCRAM with different superlattice structures on the threshold voltage and rate of change of the magnetoresistance.Firstiy,we produced GeTe/Sb₂Te₃ superlattice PCRAM cell by semiconductor technology,and optimized the technology of cell with different structure to produce stable and controllable superlattice PCRAM cell which has a high magnetoresistance,and then produced superlattice PCRAM cell which change the thickness of GeTe and Sb₂Te₃ in each period or the period of superlattice.Secondly,we measured the characteristics of the samples by instrument called B1500,and found that the samples with different superlattice structures had different threshold voltage;Then we measured the samples with an external magnetic field of 0.1T,and found that all of samples'the threshold voltage had increased and showed magnetoresistance.With the decrease of GeTe and the increase of Sb₂Te₃,the magnetoresistor change rate of the superlattice increases first and then decreases when GeTe:Sb2Te3=3:3,the magnetoresistor change rate is the highest.On other hand,the magnetoresistance change rate of superlattice increases with the decrease of its period.