Bipolar Resistive Switching Characteristics of HfO(2)/TiO(2)/HfO(2) Trilayer-Structure RRAM Devices on Pt and TiN-Coated Substrates Fabricated by Atomic Layer Deposition.
Bipolar Resistive Switching Characteristics of HfO(2)/TiO(2)/HfO(2) Trilayer-Structure RRAM Devices on Pt and TiN-Coated Substrates Fabricated by Atomic Layer Deposition.
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原子层沉积 Pt 和 TiN 涂层衬底上 HfO2/TiO2/HfO2 三层结构 RRAM 器件的双极阻变特性
DOI：
10.1186/s11671-017-2164-z
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发表时间：
2017-12
影响因子：
--
通讯作者：
Wu D
中科院分区：
文献类型：
--
作者：
Zhang W;Kong JZ;Cao ZY;Li AD;Wang LG;Zhu L;Li X;Cao YQ;Wu D
采用原子层沉积（ALD）技术，在镀铂和镀锡的Si衬底上制备了HfO2/TiO2/HfO2三层结构的电阻随机存取存储器（RRAM）器件。研究了Pt和TiN底电极对三层结构单元电阻开关性能的影响。Pt/HfO2/TiO2/HfO2/Pt和Pt/HfO2/TiO2/HfO2/TiN均表现出典型的双极电阻开关行为。两种记忆细胞在低阻和高阻状态（LRS和HRS）的主要传导机制分别是欧姆行为和空间电荷限制电流。研究发现，Pt和TiN的底电极对三层结构记忆电池的电铸极性偏好、高低电阻比和工作电压的色散有很大影响。与对称Pt顶/底电极相比，非对称Pt顶/TiN底电极的RRAM电池负形成电压较小，为- 3.7 V，设置/复位电压分布相对较窄，高低电阻比为102。电极依赖的电铸极性可以通过考虑电极与氧的化学活性、阳极上的相关反应以及HfO2/TiO2/HfO2在Pt和tin涂层Si上三层结构中氧空位浓度的不均匀分布来解释。此外，对于Pt/HfO2/TiO2/HfO2/TiN器件，TiN电极作为氧气罐在降低形成电压和提高电阻开关参数均匀性方面发挥了重要作用。
The HfO2/TiO2/HfO2 trilayer-structure resistive random access memory (RRAM) devices have been fabricated on Pt- and TiN-coated Si substrates with Pt top electrodes by atomic layer deposition (ALD). The effect of the bottom electrodes of Pt and TiN on the resistive switching properties of trilayer-structure units has been investigated. Both Pt/HfO2/TiO2/HfO2/Pt and Pt/HfO2/TiO2/HfO2/TiN exhibit typical bipolar resistive switching behavior. The dominant conduction mechanisms in low and high resistance states (LRS and HRS) of both memory cells are Ohmic behavior and space-charge-limited current, respectively. It is found that the bottom electrodes of Pt and TiN have great influence on the electroforming polarity preference, ratio of high and low resistance, and dispersion of the operating voltages of trilayer-structure memory cells. Compared to using symmetric Pt top/bottom electrodes, the RRAM cells using asymmetric Pt top/TiN bottom electrodes show smaller negative forming voltage of −3.7 V, relatively narrow distribution of the set/reset voltages and lower ratio of high and low resistances of 102. The electrode-dependent electroforming polarity can be interpreted by considering electrodes’ chemical activity with oxygen, the related reactions at anode, and the nonuniform distribution of oxygen vacancy concentration in trilayer-structure of HfO2/TiO2/HfO2 on Pt- and TiN-coated Si. Moreover, for Pt/HfO2/TiO2/HfO2/TiN devices, the TiN electrode as oxygen reservoir plays an important role in reducing forming voltage and improving uniformity of resistive switching parameters.