Study On Switching Behavior And Performance Optimization Of Organic-inorganic Hybrid Perovskite Based RRAM

The development of traditional FLASH memory based on floating grid experience bottlenecks due to its physical nature.To meet the developing demand of information storage,Great efforts are supposed to be made in researching next generation memory device.Among the several new kind memory that researchers keep eyes on,Resistance random access memory?RRAM?is one of the most competitive candidate of next generation memory due to its advantages in device structure,write or read speed,endurance and so on.For the RRAM device,materials of switching layer have strong impact on its performance.Different system of materials have special potential on different area.Among them,inorganic-organic hybrid perovskite materials take advantages of simple preparation technique,tunable band gap,brilliant photoelectric response and so on,have great significance in the RRAM application of photoelectricity and multifunction.Hence,we selected RRAM device based on CH3NH3PbI3?hereinafter referred to simplified as MAPbI3?to studiy the switching behavior and performance improvement as follow.Preparation and electrical properties of RRAM based on MAPbI3:?1?MAPb I3 film is obtained by Using two step method.RRAM device with a structure of Al/MAPbI3/FTO could loop stably and switch rapidly?less than 100 ns?;?2?The resistance state influenced by progressive pulse amplitude have been investigated.The switching mode could be changed from digital to analog by changing the amplitude of pulse.The resistance state is tunable at the range of 50?to 800?.These phenomenon indicated that RRAM based on MAPbI3 have potential in Synaptic learning and memory function;?3?The device retention influenced by compliance current have been investigated.The storage mode could be changed from nonvolatile to volatile by applying different compliance current?5 mA-500?A?.And quantum conductance phenomenon have been discovered in volatile storage,which could be useful in atomic switching or high density storage.?4?The switching mechanism have been investigated.The vacancy conductive filaments theory based on iodine ion migration is verified as the physical nature of switching by experiments.Performance improvement of RRAM based on MAPbI₃:The overproduction of iodine vacancy during electroforming process and the overgrowth of conductive filaments during cycling process could strongly degrade the device performance.In allusion to the problem mentioned above,we designed two method of visible light assisted electroforming process and introduce?-C barrier to improve device performance.?1?By using the visible light assisted electroforming process,device window have been improved from 7 to 20,power consumption have been decreased from 17.95 mW to 0.87 mW,resistance state coefficient of dispersion have been decreased from 23.02%/43.50%?HRS/LRS?to 7.93%/20.08%.Through experiment we verified that the improvement mechanism could be contribute to the active energy of iodine decreasing by visible light illuminating and parasitic capacitance effect suppressing by photo-generated carrier.?2?By introducing the?-C barrier,device window have been improved from10 to 18,power consumption have been decreased from 653?W to 74?W,high resistance state coefficient of dispersion have been decreased from 48.92%to 17.60%.Through experiment we verified that the improvement mechanism could be contribute to the iodine volatilization suppressing by the the?-C barrier.