The 3D Stacking Bipolar RRAM for High Density
POLYTECHNIC INST OF NEW YORK BROOKLYN
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For its simple structure, high density and good scalability, the resistive random access memory RRAM has emerged as one of the promising candidates for large data storage in computing systems. Moreover, building up RRAM in a three-dimensional 3D stacking structure further boosts its advantage in array density. Conventionally, multiple bipolar RRAM layers are piled up vertically separated with isolation material to prevent signal interference between the adjacent memory layers. The process of the isolation material increases the fabrication cost and brings in the potential reliability issue. To alleviate the situation, we introduce two novel 3D stacking structures built upon bipolar RRAM crossbars that eliminate the isolation layers. The bi-group operation scheme dedicated for the proposed designs to enable multi-layer accesses while avoiding the overwriting induced by the cross-layer disturbance, is also presented. Our simulation results show that the proposed designs can increase the capacity of a memory island to 8K-bits i.e., 8 layers of 32 x 32 crossbar array while maintaining the sense margin in the worst-case configuration greater than 20 of the maximal sensing voltage.
- Computer Hardware