Resistive random access memory (RRAM) is a strong candidate for next-generation memory. Despite its versatility, the sneak path current severely threatens accurate read operations, preventing RRAM from being expanded to high density array. To solve this sneak path current, here we propose a method to enhance a rectification effect through barrier height engineering. We fabricated two TiO_x-based devices, Al/TiO_x/Al devices as a control group and Cu/TiO_x/Al devices as an experimental group, and compare their rectification characteristics. As a result, a rectification ratio in Cu/TiO_x/Al devices is much larger than that of Al/TiO_x/Al devices, e.g., approximately 122 times for low-resistance-state and 251 times for high-resistance-state. Furthermore, we analyze the energy band diagram considering the bias polarity and electric-field-driven oxygen ion migration. It is confirmed that the rectification effect results from high energy barrier height between Cu top electrode and TiO_x. In addition, it is established that the high rectification ratio of Cu/TiO_x/Al devices is capable of constructing large-sized memory array with reliable read margin by simply adjusting energy barrier height

电阻式随机存取存储器（RRAM）是下一代存储器的理想选择。尽管具有通用性，但潜行电流仍然严重威胁准确的读取操作，从而阻止了RRAM扩展到高密度阵列。为了解决这种潜行电流，我们在此提出一种通过势垒高度工程来增强整流效果的方法。我们制造了两个基于TiO _x的器件，以Al / TiO _x / Al器件为对照组，以Cu / TiO _x / Al器件为实验组，并比较了它们的整流特性。结果，Cu / TiO _x / Al器件中的整流比远大于Al / TiO _x的整流比。/ Al器件，例如，低电阻状态约为122倍，高电阻状态约为251倍。此外，我们在考虑能带极性和电场驱动氧离子迁移的情况下分析能带图。可以确认，由于铜顶部电极与TiO _x之间的能垒高度高，因此具有整流作用。此外，可以确定，通过简单地调整能垒高度，Cu / TiO _x / Al器件的高整流比能够构建具有可靠读取余量的大型存储阵列。