含Ti电极的非晶钛酸锶薄膜的阻变开关特性研究

Investigation on Memory Characteristic of Resistive Switching in Amorphous SrTiO_(3-δ) Films with Ti Electrode

采用射频磁控溅射法制备Ti金属薄膜作为反应电极,结合脉冲激光沉积法在Pt/Ti/Si衬底上制备了Ti/非晶-SrTiO3-δ(STO)/Pt结构的阻变存储器件单元。器件的有效开关次数可达200次以上。利用5 mV的小电压测量处于高低阻态的器件电阻,发现在经过3.1×105s以后,两种阻态的电阻值均没有明显的变化,说明器件具有较好的保持特性。器件处于高阻态和低阻态的电阻比值可达100倍以上。在9 mA的限制电流下,器件的低阻态为500Ω,有利于降低电路的功耗。氧离子和氧空位的迁移在阻变开关中起到重要的作用,界面层TiOχ发挥着氧离子库的作用。阻变开关机制归因为导电细丝(Filaments)的某些部分出现氧化或者还原现象,造成导电细丝的形成和断开。

Ti metal films were grown as reactive electrode by magnetron sputtering technique,and resistive switching memory cells of Ti/amorphous-SrTiO3-δ（STO）/Pt were fabricated on Pt/Ti/Si substrates by pulse laser deposition.The cell can be repeated for more than 200 times.The resistances exhibit no obvious variation under a small voltage used to test the resistance in high resistance state and low resistance state after 4×105 s,implying good retention.The ratio of resistance between high resistance states and low resistance states can reach 100.Moreover,the low resistance is 500 Ω at a compliance current of 9 mA,which is favorable to reduce the power dissipation of the entire circuit.The migration of oxygen ions and vacancies would play an important role in resistive switching,and the interfaces of TiOχ acted as oxygen reservior.The switching mechanism was ascribed to reduction and oxidization in some parts of conducting filaments,resulting in formation and disruption of conducting filaments.