A Novel Three-Dimensional High Density Vertical Rram Arrays with Reduced Leakage Current

Abstract

NAND flash is the most widely used non-volatile memories due to its low cost and rewritable properties. However, some problems exist in NAND flash that need to be solved, such as low writing and reading speed, high operating voltage, and relatively large cell dimensions. Next generation memories, especially resistive random access memory (RRAM) could improve these problems. The technologies of 3D vertical architecture have made a major breakthrough in establishing high-density memory structures. Combined with an array structure, a 3D high density vertical resistive random access memory (VRRAM) cross-point arrays are able to efficiently increase the device density in vertical direction. In this work, a novel 3D VRRAM arrays which contains two VRRAM cells (Pt/ ZnO/ Al and Pt/ ZnO/ Ti) and one normal layered RRAM (Al/ Al2O3/ Ti) at each cross point were constructed. The Al2O3 based device could operate under a lower compliance current, where contained higher resistance than ZnO based cells. With the controlling of compliance current, the leakage current between VRRAM cells and Al/ Al2O3/ Ti cell could be effectively reduced, therefore, the neighboring cells could be operated independently. We demonstrated the introducing of VRRAM structure could achieve high density advantage in vertical direction, and the adjacent cells in 3D vertical structure could be operated independently with scarcely leakage current. The shrinkage of leakage current enhance the stability of devices and increase the feasibility of high density VRRAM structure applications. Figure 1