Research On Photoelectric Hybrid Function Of Chalcogenide Memory And Its Performance Optimization

With the advent of the big data era,people have put forward higher demands on the speed,power consumption and cost of high-performance storage and computing.Therefore,a new type of non-volatile memory device that can realize the functions of data storage and calculation has attracted widespread attention.The new memory device with integrated memory and computing functions can avoid the problems of energy loss and signal delay caused by the separation of storage units and computing units faced by the traditional von Neumann architecture.Chalcogenide-based phase change materials are considered to have high potential in the research of new memory devices and have received extensive attention.Among the chalcogenides,the research on Ge₂Sb₂Te₅（GST）is the most mature.Under certain conditions,this material can realize the mutual conversion between crystal phase and amorphous phase,thereby changing its optical and electrical properties.At present,most of the optoelectronic applications based on GST materials are to change the material through electrical equipment,and then study the optical properties of the device before and after the phase change.This article is to design a photoelectric hybrid device based on GST material,which can show two different application functions in optical and electrical directions before and after phase transition.In this paper,the finite element analysis software COMSOL Multiphysics is used to establish the optical model and electrical model of the chalcogenide optoelectronic hybrid memory device.In the optical model,the reflectivity of the GST surface to near-infrared light waves under different crystal phase states is studied.Since the thickness of each layer of the device will have more or less influence on the reflectivity of the spectrum,this factor is also included in the simulation process.A detailed study was conducted to determine a reasonable size for the hybrid device.In the electrical model,the mechanism of the phase transition of the GST layer under electrical excitation is studied,and the electrical pulse is applied to the probe to cause the phase transition of the material,thereby realizing the writing and erasing of data.Writing in the amorphous state in the all-crystalline layer or writing in the crystalline state in the all-amorphous layer can realize data recording and erasing on the device,and both can show extremely high data storage density.Therefore,this paper conducts research and analysis on these two situations,and performs data reading operations.The simulation results show that writing amorphous data in a device with a fully crystalline layer will result in more accurate reading results.In terms of expanding data storage density,in addition to designing probe phase-change memory devices,this paper also studies phase-change memory arrays,and GST-based phase-change memory arrays have been used in commercial fields.However,under high-density integration conditions,thermal crosstalk will occur in the array,which will affect the stability and accuracy of the memory array.In this paper,a new phase-change memory with blade structure is extended to a 3×3 array,and the thermal crosstalk phenomenon in its active state is studied.By changing the unit device spacing,structure size,external excitation and array scaling,the influence of these factors on the thermal crosstalk phenomenon of the array and the suppression ability of the structure to the thermal crosstalk phenomenon are studied.Finally,a scheme to improve the insulating layer material is proposed to further suppress the thermal crosstalk effect in the array.