An 8 Mb Multi-Layered Cross-Point ReRAM Macro With 443 MB/s Write Throughput

TLDR: An 8-Mb multi-layered cross-point resistive RAM (ReRAM) macro has been developed with 443 MB/s write throughput (64-bits parallel write per 17.2-ns cycle), which is almost twice as fast as competing methods.

Abstract: Nonvolatile memories with fast write operation at low voltage are required as storage devices to exceed flash memory performance [1–3]. We develop an 8Mb multi-layered cross-point ReRAM macro with 443MB/s write throughput (64b parallel write per 17.2ns cycle), which is almost twice as fast as existing methods, using the fast-switching performance of TaO x ReRAM [4] and the following three techniques to reduce the sneak current in bipolar type cross-point cell array structure in an 0.18μm process. First, memory cell and array technologies reduce the sneak current with a newly developed bidirectional diode as a memory cell select element for the first time. Second, we use a hierarchical bitline (BL) structure for multi-layered cross-point memory with fast and stable current control. Third, we implement a multi-bit write architecture that realizes fast write operation and suppresses sneak current. This work is applicable to both high-density stand-alone and embedded memory with more stacked memory arrays and/or scaling memory cells.