C-Doped SbTe-Based Phase Change Film And Memory Devices

Phase change memory（PCM）is one of the next generation non-volatile memory.Compared with other memory devices,phase change memory has the advantages of non-volatile,fast set/reset speed,low power consumption and CMOS technology compatibility,which is an important topic for researchers in the integrated circuit industry.At present,the most well-studied and widely used phase change material is Ge₂Sb₂Te₅（GST）material.However,the shortcomings of GST,such as slow crystallization speed,limit the use of GST materials in the IC industry.Compared with GST materials,Sb Te-based materials operate the advantages of ultra-fast operation speed and low power consumption.Recently,the largest number of the studies conducted around Sb Te-based materials were related to Sb₂Te and Sb₂Te₃.These materials also have their respective defects,which cause the poor performance of the PCM devices prepared with these materials.On the basis of related research,this paper proposes high-purity carbon（C）doped Sb-Te-based materials,and prepares corresponding devices.It is expected that the performance of materials and devices can be improved as much as possible while maintaining the rapid set/reset ability of Sb-Te-based materials.The main results obtained in this paper are as follows:（1）Systemic researching about the C-doped Sb₂Te（C-Sb₂Te）phase change material.Using magnetron sputtering technology prepared C-doped Sb₂Te phase change film,and preparing a memory device with C-Sb₂Te phase change material.The crystallization temperature,data retention force,change in crystalline grain size and bonding situation were systematically studied in the C-Sb₂Te phase change film.C-doping can significantly increase the crystallization temperature and data retention force of Sb₂Te materials,doping can increase the crystallization temperature of Sb₂Te material to 206℃,and the 10-year data retention force temperature would be higher than 130℃.Based on the results of X-ray diffraction,C-doping also refined the grains of Sb₂Te.By analyzing the X-ray photoelectron energy spectrum,it is known that C will interrupt part of the Sb-Te bond and form the C-Te,C-Sb and C-C bond,which would hinder the crystallization process of Sb₂Te.According to the electrical test results of the C-Sb₂Te device,the device can complete the phase change operation under a pulse of 10 ns pulse width.The high and low resistance of the device is stable at about 100:1 ratio,and the number of device cycles exceeds3×10⁴.（2）C-Sb₂Te₃phase change films with different C-doped content or different thickness were prepared,and the characteristics of C-Sb₂Te₃phase transition films were researched.In the R-T test,the crystallization temperature of the film significantly increases with the rise of carbon content;while decreasing the film thickness changes the resistivity of the material and increases the crystallization temperature.The result of the X-ray photoelectron energy spectrum shows that the incorporated carbon may form a C-C bond and interfere with the crystallization process of Sb₂Te₃.According to the results of electrical tests,the performance of the device prepared with C-Sb₂Te₃is better than the one prepared with C-Sb₂Te in all aspects.The C-Sb₂Te₃device can phase change with a pulse of 6ns pulse width and cycles of set/reset has a maximum number of more than 1×10⁵.Select part of the substrates,performing H-ion cleaning on the substrate before preparing the C-Sb₂Te₃device.The prepared C-Sb₂Te₃device has a more stable high-low resistance ratio than those without pre-cleaning treatment.