Analysis of read margin and write power consumption of a 3-D Vertical RRAM (VRRAM) crossbar array

In this paper, the read margin (RM) and write power (WP) for various 3-D vertical resistive random-access memory (VRRAM) architectures and bias schemes are analyzed. The optimized bias scheme for each of the read and write operations is demonstrated using HSPICE simulation. The ground and 1/3 bias schemes are desirable for reading a row of cells and a single cell, respectively, whereas the 1/2 bias scheme is more suitable for the write operation. The RM is strongly influenced by the number of word line (WL) layers, which determines the number of half-selected cells. The WP is predominantly affected by the in-plane array size rather than the number of WL layers, as the majority of the power is consumed in the selected WL. Only slight differences between the WL plane and WL even/odd structures are observed in the RM and WP. Therefore, due to the same performance and a double cell bit, a WL even/odd structure is more promising than a WL plane structure for the VRRAM architecture.