Research On The Resistive Switching Characteristics Of The Pt/HfO₂/Al₂O₃/TiN Structure

With the shrinking feature size of integrated circuits,flash memory,which occupies the mainstream market of memory,will face severe challenges.Gradually approaching the physical limit of size reduction will lead to a series of problems,such as gate leakage etc.Future information stores will inevitably rely on emerging non-volatile memories such as Phase Change Random Access Memory?PRAM?,Ferroelectric Random Access Memory?FRAM?,Magnetic Random Access Memory?MRAM?,and Resistive Random Access Memory?RRAM?.Among them,RRAM is the best competitor for the next generation of non-volatile memory because of its fast response,low power consumption,easy 3D integration and compatibility with traditional CMOS processes.Many binary metal oxides,such as ZnO,ZrO₂,NiO and HfO₂,have reproducible resistance characteristics and can be used as a material for a resistive dielectric layer.Among them,HfO2 has attracted much attention due to its characteristic high-k characteristics.In this paper,Pt/HfO₂/Al₂O₃/TiN devices were fabricated by ALD method.The effects of different thicknesses,different electrode sizes and different test temperatures on the resistance switch performance of laminated films were investigated.?1?Comparing the electrical characteristics of Pt/HfO₂/Al₂O₃/TiN structural devices with thicknesses of HfO₂/Al₂O₃ resistive dielectric films of 5 nm/5 nm,5 nm/3 nm,7 nm/3nm,and 3 nm/7 nm respectively,the resistance switching characteristics are typical bipolar resistance switching characteristics,the switch ratio is larger than 10.When the thickness of HfO₂/Al₂O₃ is 7 nm/3 nm,the retention performance and fatigue resistance are the best.?2?Comparing the electrical characteristics of Pt/HfO₂/Al₂O₃/TiN structure devices under 5 different Pt top electrode sizes?100?m×100?m,70?m×70?m,50?m×50?m,40?m×40?m,30?m×30?m,respectively?,the results show that the electrode size mainly affects the uniformity of the resistance parameters of the device.When the size of the Pt top electrode is 100?m×100?m,the resistive parameter fluctuation of the device is minimal.?3?The electrical properties of Pt/HfO₂/Al₂O₃/TiN structural devices were tested at RT,50?,65?,85?,105? and 125?,respectively.When the temperature rises to 125?,the device fails.Tests have shown that as the temperature increases,the resistance of the Pt/HfO₂/Al₂O₃/TiN devices(R_LRSRS and R_HRS)fluctuates more and more.When the temperature approaches the failure temperature,the fluctuations of the device's transition voltages(V_Setet and V_Reset)also become large.