VLSI memory technology: Current status and future trends

In this paper, first, newly developed state-of-the-art VLSI memory chips, exemplified by DRAM, SRAM, and Flash memory, are discussed. Second, technology trends concerning standard DRAM's, embedded memories, and low-voltage memories are reviewed. For standard DRAM's, memory cells with high cell capacitance, high-speed subsystem technologies (such as synchronous operations, pipelining/prefetching, and use of packet protocols), and small-swing interfaces are investigated. And regarding embedded memories, the advantages and the challenges involved in reducing process costs are presented. Moreover, the use of special circuits to reduce subthreshold current in low-voltage memories is summarized, citing examples of recent advancements. Finally, it is emphasized that a unified memory cell, such as a gain cell (which includes all the advantages of the existing memory cells) must be developed in the near future.