Research On Re-Sb-Te Phase Change Thin Films And Devices For High Speed And High Thermal Stabilization Photoelectric Storage Applications

Phase change memory is favored by domestic and foreign researchers and the industry due to its excellent characteristics such as non-volatility,fast erasing,miniaturization,good process compatibility,and low power consumption.It is known as one of the best candidates for the next generation of non-volatile memory.Ge₂Sb₂Te₅(GST)is a phase change material that has been widely studied and used,but GST has shortcomings such as slow crystallization speed,high operating power consumption,and large density changes.Compared with GST,Sb-Te binary materials have ultra-fast operation speed and lower operation power consumption.Therefore,Sb-Te series materials have received more and more attention from scientific researchers in recent years.Among Sb-Te system materials,Sb₂Te and Sb₂Te₃ are the two most studied materials in recent years.However,Sb-Te series materials also have some disadvantages,such as lower crystallization temperature and poor thermal stability.Based on this,this paper proposes a super-hard refractory rhenium(Re)doped Sb-Te phase change material to improve the performance of the material and the device without affecting the operating speed.The main results obtained in this paper are as follows:(1)The Re-doped Sb₂Te(Re-Sb₂Te)film has been prepared by magnetron sputtering technology,and the storage device based on Re-Sb₂Te film has been prepared by combining semiconductor process technology.The crystallization characteristics,data retention,density change rate,bonding situation and microstructure of Re-Sb₂Te films have been systematically studied.It was found that the doping of Re into Sb₂Te significantly increased the crystallization temperature and data retention of materials.The maximum crystallization temperature of Re-Sb₂Te reached 205.9?,and the 10-year data retention temperature reached 152?.According to the X-ray diffraction results,the doped Re atoms refine the crystal grains.By analyzing the X-ray photoelectron spectroscopy,it can be known that Re will break the Sb-Te bond and form a Re-Te bond with the Te atom,and the Sb atom will form a bond with itself.The electrical test about the Re-Sb₂Te device shows that it can complete the phase change operation under a 10 ns pulse.The device's high and low resistance ratio is stable at about 10²,and the number of cycle operations of the device reaches 4×10⁴ times.In addition,the density change rate of Re-Sb₂Te material is 4.2%,which is much smaller than that of traditional GST materials(6.5%).(2)Sb₂Te₃ material is used as the matrix to prepare Re-Sb₂Te₃ phase change films with different Re content.Study the characteristics of the Re-Sb₂Te₃ phase change film,including the crystallization of the film,the density change rate,etc.Select the best components from a set of Re-Sb₂Te₃ films to prepare Re-Sb₂Te₃ memory devices.In the resistance-temperature test,the crystallization temperature of the film and the ratio of high to low resistance increase with the increase of Re content.As a result of X-ray photoelectron spectroscopy,the doped Re replaced a small amount of Sb atoms in Sb₂Te₃,thereby forming a Re-Te bond with Te.In the film thickness change test,the density change rate of Re-Sb₂Te₃ film is only 3.6%,which is smaller than those of Sb₂Te₃(8.7%),GST(6.5%)and Re-Sb₂Te(4.2%)films.Electrical tests show that the performance of the Re-Sb₂Te₃ device is better than those of the Re-Sb₂Te,and the Re-Sb₂Te₃ device can stabilize the phase change under a 6 ns pulse.Devices based on Re_0.12(Sb₂Te₃)films could reach about 5×10⁴ cycles of endurance,and the power consumption of the devices was lower than that of the Re-Sb₂Te device.Devices based on Re-Sb₂Te₃ films not only operate fast but also have low operating voltage.Therefore,Re-Sb₂Te₃ is a phase change material with high speed and low power consumption.