eMRAM: Ready to Roll!

By: Dave Eggleston

There’s been a lot of news recently about embedded MRAM (eMRAM), and for good reasons.  The technology is rapidly accelerating from research and development to commercialization at multiple foundries, and is now being adopted by chip designers. Most notably, GLOBALFOUNDRIES just announced the availability of its 22FDX® 22nm FD-SOI eMRAM for system-on-chip (SoC) designers, with released PDKs, off-the-shelf macros, and MPWs for customer prototyping. With risk production expected from GF and other foundries by the end of 2018, MRAM is shaping up to be a big technology and market disruptor right now, promising to replace embedded Flash, and augment SRAM in MCUs and SoCs for automotive, IoT, consumer and industrial systems. Over the horizon, FinFET processes with eMRAM will also appear, bringing new capabilities to future storage, networking and datacenter systems.

Supercharged Performance

MRAM technology has been under development for decades – in parallel with several other non-volatile memories including RRAM, Phase Change, Carbon Nanotubes, Ferroelectric – and recently, eMRAM has clearly taken the lead position among all emerging embedded memory technologies. Why? eMRAM offers SoC designers very significant performance advantages:

• Very fast write speeds (<200ns)
• Extremely high endurance (~10E8 cycles)
• Operation from logic Vcc (no high voltage pumps needed)
• Low energy writes (10x lower than eFlash)
• Zero bitcell static leakage (0 pA vs. >50pA for a SRAM bitcell)

Coupled with the performance advantages, eMRAM enjoys a significantly higher level of technology maturity versus other emerging NVM options, featuring:

• Well understood magnetism physics
• Simple, controllable switching mechanism (no forming, or stepped writes needed)
• Low incidence of single bit failures
• Demonstration of multi-Mb arrays at sub-28nm
• Achieving high yield, with excellent reliability
• Full integration into advanced foundry production processes

eMRAM simultaneously delivers bit density, speed, endurance, coupled with low power consumption and non-volatility. The combined advantages of superior performance and technology maturity for eMRAM are key factors for foundry customers deciding to use eMRAM for their sub 28nm products.

Hit the Road Running

eMRAM simultaneously delivers bit density, speed, endurance, coupled with low power consumption and non-volatility. The combined advantages of superior performance and technology maturity for eMRAM are key factors for foundry customers deciding to use eMRAM for their sub 28nm products.

Historically, eMRAM has not been perceived as ready for commercialization because of several manufacturing and reliability barriers: material complexity, poor data retention at hot temperatures, susceptibility to external magnetic fields, and finally, difficult and expensive manufacturing.

Tough challenges to overcome, but to move the needle from an unreliable to reliable technology the industry has directly tackled the issues of materials and manufacturing complexity. As a part of this effort, major fab equipment makers, along with foundries, pioneered eMRAM specific PVD and Etch equipment that achieves 20 wafers per hour (wph) throughput, which enables a competitive manufacturing cost.

Moreover, GF has specifically improved eMRAM reliability, by modifying the magnetic materials to deliver outstanding data retention and magnetic immunity, including:

• Less than 10ppm bit error rate through 260°C solder reflow
• 15 year data retention at 125°C
• More than 1000 Oe magnetic immunity

In other words, many of the past barriers for eMRAM commercialization have now been overcome – solved by the collective efforts of the foundries and major fab equipment makers in making eMRAM reliable and manufacturable.

Crank up the “Killer Combo”

In light of these new advancements in reliability and manufacturability, high-volume market opportunities have now opened up for eMRAM. The market opportunity further expands with the widespread commercialization of fully-depleted silicon-on-insulator (FD-SOI) as a substrate.

eMRAM on FD-SOI brings together best-in-class capabilities, creating an irresistible “Killer Combo” vs. other bulk silicon offerings. Unlike eFlash, which is built down into the silicon, eMRAM’s magnetic element is built up in the metal layers, so it is more easily implemented into a logic process such as FD-SOI with no impact on FEOL transistors. Additionally, eMRAM’s higher endurance, faster write speed increases SoC performance, and the low write energy reduces power consumption by more than 80 percent (vs. 28nm bulk silicon with eFlash).

In particular, GF’s industry leading 22FDX eMRAM platform provides excellent scaling, outstanding RF IP, ultra-low leakage, power island control – and (finally!), eMRAM macros with either eFlash or SRAM interfaces. For the first time, the versatility of GF’s 22FDX eMRAM enables ultra-efficient memory subsystems that power cycle with no time or energy penalty, making it suitable for a broad spectrum of applications.

eMRAM is finally here; ready for SoC designers to take advantage of the superior performance and technology maturity, with GF’s 22FDX eMRAM delivering excellent reliability and manufacturability.

Design your Killer Product today, using GF’s 22FDX “Killer Combo”!

To test drive GF’s 22FDX and embedded memory offerings:

• GF’s Embedded Memory Technology Brief
• GF’s VLSI Symposium Technical paper on eMRAM for GP-MCU Applications
• GF’s IMW Technical paper on eFlash for Automotive MCUs
• GF’s 22FDX Technology Brief