Research On Nitride Resistive Switching Devices With Local Doping Of Resistive Switch Layers

In recent years,with the rapid development of the information industry,the demand for non-volatile memory has increased dramatically.However,the traditional semiconductor memory has gradually approached its physical bottleneck,and seeking new storage models with higher performance,faster speed,greater storage density,stronger reliability and lower power consumption has become the current research hotspot.Among several new random access memories,the resistive random access memory receives wide attention for its simple structure,low cost,good retention and high endurance,with the great potential to become the next generation of mainstream memory.As a wide-gap semiconductor material,silicon nitride has excellent performance such as low working current and long-time data preservation,which is favored by researchers.This paper studies the effect of local metal doping in the resistive layer on the device performance,further improves the performance of the Si N_x-based RRAM device,and studies the microscopic mechanism of the resistance.The specific studies are as follows:1.Study of SiN_x-based RRAM devices with local Ru doping in the resistive layer.The influence of the metal doping range in the device resistive layer is analyzed by controlling the preparation process of the device.By comparing the electrical properties of each group of devices,it is found that each group of local Ru doping devices shows the resistive switching properties of bipolar type,and the forming voltage and the number of initial process period decrease with the doping range.Through the analysis and thorough discussion of the conductivity mechanism and resistive-switching model,it is found that changing the incorporation range of Ru can adjust the contact barrier between the resistive layer and the top electrode,make the regular connection and disconnection of the conductive channels regular,and the device set/reset voltage decreases and increases the stability.Finally,by comparing the performance of the devices of different sizes,it is found that making 7nm Ru doping at the top of the resistive layer can make the device have better properties,and reducing the size of the device can increase the device resistance window and improve the stability.2.Effect of local Ta doping of the resistive layer on the device performance.By comparing the electric properties and current conduction mechanism of metal Ta doping devices in different positions in the resistive layer,the influence of metal doping positions on the device performance is analyzed.Compared with the devices without the resistive layer doping,all the devices with local Ta doping in the resistive layer show forming-free characteristics and show stable resistive switching properties without the initial process.By analyzing the current conduction mechanism of the device,it is found that the incorporation of metal Ta introduces more defects into the resistive layer and changes the current conduction mechanism of the device.At the same time,Ta concentrates the local electric field inside the resistive layer,which makes the connection and disconnection of the conductive wire in the device more regular,and improves the stability of the device.As the conductive wire tends to break off at the top electrode/resistive layer interface,the top Ta doping of the resistive layer provides the device with the best stability.Moving the position of Ta doping appropriately allows the device to maintain high stability while having a larger resistance window.Finally,the effect of the device size on the performance is also investigated.It is found that the change of device size has less impact on I-V characteristics,and the device conductivity mechanism is consistent in different resistance states.These devices can be better scalable by local Ta doping and have the potential for applications in small sizes.