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22 EE|Times EUROPE — The Memory Market

SPECIAL REPORT: MEMORY TECHNOLOGY
Emerging Memories May Never Go Beyond

Niche Applications

By Gary Hilson

t is time for a frank discussion about
emerging memories. Many have now been
percolating for decades with the promise of
Idisplacing established incumbents such as
DRAM and NAND flash.
But will emerging memories ever see the
light of day? Despite research breakthroughs
and new patents on potentially disruptive
technologies, and despite the slowing of
Moore’s Law, DRAM and NAND technologies
continue to advance. That means the goalposts Comprising materials that can be used on existing production lines, Weebit Nano’s
are always moving for possible replacements. ReRAM technology uses two metal layers with a silicon oxide layer between. (Source: Weebit)
MRAM, ReRAM, FRAM, and PCRAM are often
discussed in the context of emerging use cases
such as automotive, the industrial internet of things, edge computing made some inroads in turning out embedded ReRAM devices to drive
and sensor nodes, and even AI and machine learning. But they often fall revenue that can fund discrete development efforts. In collaboration
short where it counts: reliability and longevity. with research partner Leti, Weebit Nano announced in late 2019 that
There are, in fact, niche applications for next-generation memories, it would ramp efforts to solve the selector problem necessary to make
just as there for are for legacy technologies, which still reap healthy discrete ReRAM commercially viable. Meanwhile, it continued to
profit margins in smaller market segments. The reason? Legacy systems explore the memory’s potential for neuromorphic and AI applications.
often represent the best solu- CEO Coby Hanoch has previously told EE Times that Weebit is still
MRAM, ReRAM, FRAM, tion for a specific problem. a memory startup that must build a revenue stream from embedded
Emerging memories have
products in order to advance on other fronts.
and PCRAM are often been around for decades. The appeal of its ReRAM technology is that it leverages materials
discussed in the context While some have found that can be used in existing production lines.
The other emerging memory seeking to flourish as a discrete tech-
a measure of commercial
of emerging use cases success as embedded technol- nology is ferroelectric RAM (FRAM), which uses a ferroelectric instead
of a dielectric layer to achieve nonvolatility. While fabrication steps are
ogies, they have also lagged
such as automotive. as cost-effective alternatives similar to DRAM’s, FRAM functionality is more like flash.
Having been around for roughly 35 years, FRAM is arguably the most
But they often fall to discrete memories. That, successful of the emerging memories in that it has made headway in
despite higher performance,
short where it counts: endurance, and retention or embedded applications and has the potential to reach higher densities.
reliability and longevity. reduced power consumption. FRAM’s nonvolatility and low power consumption are desirable charac-
teristics for many applications, and there are small niches for
Magnetoresistive
random-access memory the technology.
(MRAM) was first developed in the 1980s and promoted as a universal For example, Cypress-Infineon offers its Excelon FRAM for automotive
memory. Unlike other memory technologies, MRAM stores data as and industrial applications, with densities as high as 8 Mb in low-pin-
magnetic elements rather than electric charge or current flows. count, small-package options. The Excelon family was specifically
Performance-wise, MRAM is similar to SRAM because of its use of designed for the high-speed, nonvolatile data logging needed for autono-
sufficient write current. But that dependence also hampers its ability to mous vehicles. It is also used in medical, wearable, IoT sensor, industrial,
compete at higher densities with DRAM and flash. and other advanced automotive applications. Significantly lower power
While MRAM pioneers such as Everspin have seen some success in consumption, data retention, and radiation resistance make FRAM a via-
the embedded market for discrete applications and even demonstrated ble replacement for E PROM and NOR flash. Implanted medical devices
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that MRAM can handle the extreme environments of automotive appli- that must function for up to a decade are one example.
cations, it remains a niche memory. Elsewhere, Ferroelectric Memory Company (FMC) of Germany fore-
Similarly, resistive RAM (ReRAM) has yet to mature as a viable sees higher-density, viable storage-class memories. FMC is exploring
discrete memory; even its success in the embedded market has been the potential of hafnium oxide to help create the larger transistors
limited. Adesto Technologies, recently acquired by Dialog Semiconduc- needed for the technology to achieve higher densities that can be
tor, was one of the first companies to bring commercial ReRAM devices cost-effectively manufactured.
to market with its CBRAM technology. CBRAM’s appeal included lower The ability to control costs while scaling manufacturing is critical
power consumption, fewer processing steps, and lower voltages com- if emerging memories are to become viable alternatives to DRAM and
pared with conventional embedded flash technologies. It also exhibited flash, even if only for niche applications. None of the appealing char-
radiation tolerance for space and medical applications. acteristics of MRAM, ReRAM, FRAM, or phase-change RAM (PCRAM)
Several companies have been developing ReRAM technologies over ultimately matter if manufacturing costs are excessive. Even 3D NAND
the past two decades, but the approach still faces integration and went through growing pains, despite offering numerous benefits over
reliability challenges. Like MRAM developers, ReRAM vendors have its planar predecessor.

DECEMBER 2020 | www.eetimes.eu