Research On The Optimization Of The Resistive Switching Characteristics Based On VOx

Resistive random access memory(RRAM)is a new type of nonvolatile memory,which has the advantages of fast read-write speed,high storage density,low power consumption,more erasing times,low cost and compatible with conventional CMOS technology,and it is considered as one of the strongest competitor of next generation nonvolatile memory,and attracted a lot of attention of researchers.In this paper,VOx thin film and the RRAM of Ag/VOx/Al and Ni/VOx/Al are studied.The main research includes the following contents:1.In this paper,VOx thin films were prepared using V2O5 as the sputtering target and using silicon wafer as the substrate.Then surface morphology and crystal orientation of VOx prepared under different conditions were investigated by changing the oxygen partial pressure,annealing temperature and annealing time.The results indicated that the growth rate of VOx film decreases with the increase of oxygen partial pressure;under the condition of nonannealing,the roughness of VOx film is first decreasing and then increasing with the increase of oxygen partial pressure;under the condition of 200 annealing temperature,the roughness ?of films is first decreasing and then increasing with the increase of annealing time;when the annealing time is 150 seconds,the roughness of VOx film is first decreasing and then increasing with the increase of annealing temperature;in the various oxygen partial pressure and annealing conditions,the peak intensity of V2O5(-131)is the largest.2.The Ag/VOx/Al structure of RRAM has been researched.Top electrode Ag and bottom electrode Al were prepared using magnetron sputtering and electron beam evaporation equipment,respectively,and the electrical behavior of Ag/VOx/Al under different oxygen partial pressure ratio,different annealing temperature and different annealing time were studied.Then the better performance of the device has been obtained.The results indicated that the performance of the device is best when the oxygen partial pressure is 15% and 16.67%,for the non-annealed Ag/VOx/Al device;when the annealing temperature is 200?,the resistive switching performance of the device annealed about 150 seconds is the best;when the annealing time is 150 seconds,the resistive switching performances of the device annealed about 200 ?and 300 ?are the best;The high resistive state(HRS)and the low resistive state(LRS)are controlled by space charge limited current mechanism(SCLC)and ohmic mechanism,respectively.And the resistive switching mechanism of the device is metal conductive filament mechanism.3.The Ni/VOx/Al structure of RRAM has been researched,the electrical characteristics and the mechanism of the Ni/VOx/Al device are analyzed in detail.The results indicated that the Ni/VOx/Al device shows bipolar resistive switching behavior,low resistive state(LRS)nonlinearity,and good retention;the resistances of HRS and LRS are inversely proportional to current compliance,and the resistance is decreasing with the increase of the current compliance;both the high resistive state and low resistive state in negative voltage region are controlled by space charge limited current mechanism,and the resistances of the HRS and LRS in low positive region are controlled by Schottky emission mechanism.The reason for the resistive switching of device is the trapping and detrapping electrons of defects.