At the 2018 Semicon Conference in San Francisco, a number of industry experts gave insights on developing emerging memory technologies that may either claim new markets or displace incumbent’s technologies. These emerging memories include magnetic random access memory (MRAM), resistive RAM (ReRAM), phase change memory (PCM) and ferroelectric RAM (FeRAM). Coughlin Associates and Objective Analysis are the authors of Emerging Memories Poised to Explode: An Emerging Memory Report.

Jim Handy from Objective Analysis said that a predominant driver for one memory to replace another is that its manufacturing volume increases to the point that its cost declines faster than the incumbent. This was the case for NAND flash over DRAM in about 2004 and may happen for one of the emerging memory technologies sometime in the next decade for SRAM, NOR Flash and possibly DRAM, as shown below.

Even with 3D NAND, flash memory may reach scaling limits sometime in the next decade. There are distinct possibilities that NAND flash and DRAM could face increasing competition from the emerging memories. For NAND, this could be ReRAM and for DRAM, this could be MRAM. This possible transition in-memory technologies is shown below.

Everspin is the leading MRAM company, having shipped over 70 million units for a number of different applications. They have a manufacturing partnership with Global Foundries for Spin Tunnel Torque (STT) MRAM, with Global Foundries supplying wafers to Everspin for standalone devices and Global Foundries focusing on MRAM in embedded devices. Norm Armour spoke for Everspin and Martin Mason spoke for Global Foundries at the Semicon session. Everspin has announced 256 Mb and 1 Gb STT MRAM chips and technologies to enable operation for high endurance and high temperature tolerance. The figure below shows the Everspin advanced MRAM chips.

In order to reach higher production volume, MRAM will need to be integrated into CMOS production lines. This involves dealing with materials and processes that are foreign to conventional CMOS production. Throughput improvements and more efficient production of MRAM chips is also required in order to reach high volume production. Global foundries says that use of MRAM as on-chip memory allows larger memories for multi-core architecture in a more compact space than SRAM and saves from 10X to 200X on power versus an off-chip memory solution as shown below.

Andy Walker spoke for Spin Transfer Technologies (STT), another MRAM memory company. He pointed out that having memory on the processor chip has a big positive impact on performance and that conventional DRAM technology is reaching limits in how dense it can get. He also gave the case for Storage Class Memories that have persistence and can act as NAND and DRAM caches. STT offers a stochastic magnetic tunnel junction (MTJ) STT MRAM using a Precessional Spin Current Structure, that it says can avoid some of the retention/endurance trade-offs with conventional STT MRAM.

STT says that these changes to STT MRAM can help it replace SRAM and eventually DRAM.

George Minassian, CEO of Crossbar, a Silicon Valley resistive RAM (ReRAM) company spoke about the future of ReRAM memory. He pointed out that ReRAM can scale below DRAM (he said sub 10 nm) and only involves 2 extra masks and three extra films. He indicated that 1 Tb per a single die was possible and that ReRAM uses 175X less power than SRAM. Crossbar seems ReRAM competing favorably with MRAM for advanced memory applications.

ReRAM can be used for advanced memory storage for applications such as image recognition and AI, using lower power than SRAM and DRAM. The company has advanced concepts for using ReRAM such as a high-density ReRAM tile structure.

Imec is a research consortium located in Belgium. They are engaged in research on technology and applications of most of the emerging memory technologies. These technologies range from fast memories such as STT MRAM, ReRAM, and FeRAM to possible archiving on DNA. Interestingly imec is also interested in recycling critical elements from storage and memory devices after they have been retired. The figure below shows their view of the memory and storage technologies that imec is working on.

Semicon includes exhibits and discussion around solid-state technology and manufacturing. One of the most important drivers for semiconductor technology is memory devices. This session at the 2018 Semicon showed that the industry is busy developing many options for future memory and storage to support a growing number of applications.

By: DocMemory
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