Nikkei Electronics Asia --May 2010
Analysis
Successor to Post Flash Memory Approaching Volume Production

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May 1, 2010 00:04 Motoyuki Oishi

The development of emerging memory to replace flash memory and dynamic random access memory (DRAM) is approaching a major turning point. Resistance-change memory (ReRAM) and spin-injection magnetoresistive RAM (MRAM) utilizing perpendicular magnetization are two examples of new memory technologies appearing for the first time at the International Solid-State Circuits Conference (ISSCC), the major event for semiconductor circuits of more than a certain scale demanding prototyping. The potential capabilities of the new memory designs exceed the predictions of many engineers.

"We will begin small-lot production of 64Gbit chips, or possibly even 256Gbit chips in 2012." says Christophe Chevallier, Vice President of Design Engineering at Unity Semiconductor Corp. of the US.

A venture business developing new memory technologies, Unity has announced a replacement for NAND flash memory, the recording medium of choice in memory cards and solid state drives (SSD). Dubbed CMOx, the developed resistance-change memory is more cost-competitive than NAND flash memory, and the firm hopes to use it to capture the huge existing market. Following the paper presented at ISSCC 2010, the international semiconductor technology conference held in early February 2010, the company disclosed its plans in an interview.

Cost Competitiveness Beats NAND

Unity's CMOx memory seems to symbolize the fact that the development of memory to succeed flash memory and DRAM is at a turning point (Fig.1). R&D into emerging memory has generally concentrated on constituent technologies such as memory cells, but now chip-level prototyping has become possible, with the potential for large-scale commercial rollout. One example is the spin-injection MRAM using perpendicular magnetization, which appeared at ISSCC for the first time ever. Toshiba Corp. of Japan, the developer, seems determined to leverage the strengths of perpendicular magnetization technology to replace DRAM.

Fig.1 Emerging Memories Gain Momentum
The development of emerging memories to replace flash memory has entered a new stage. The way is pretty clear now for phase-change memory to replace NOR flash memory, and efforts to replace NAND flash memory and DRAM with emerging memory are accelerating. Diagram by Nikkei Electronics based on material courtesy Toshiba.

Phase-change memory (PCM), which appeared at ISSCC just a bit earlier, has also made significant technological progress. At ISSCC 2010, Numonyx, Inc. of Switzerland announced a 1Gbit chip with a chip area of only 37.5mm2, offering the possibility of a NOR flash memory replacement. According to a source at the firm, the chip specifications are "based on NOR flash memory legacy specs, with bit-unit write."