MRAM data retention improved from 1 hour to 1 year with other gains

Spin Transfer Technologies has developed vastly improved MRAM memory using its unique Precessional Spin Current (PSC) structure. The results from advanced testing of the PSC structure confirm that it will increase the spin-torque efficiency of any MRAM device by 40-70 percent — enabling dramatically higher data retention while consuming less power. This gain translates to retention times lengthening by a factor of over 10,000 (e.g., 1 hour retention becomes more than 1 year retention) while reducing write current. Improved efficiency is critical for enabling MRAM to replace SRAM and DRAM in mobile, datacenter and AI applications, as well as for improving retention and performance in high-temperature automotive applications.

New MRAM Benefits

* Increase of the spin-torque efficiency by up to 70 percent
* Demonstration of the efficiency gain across a range of sizes (40-60nm) and temperatures (30°C to 125°C)
* Increase of the thermal energy barriers by 50 percent corresponding to an increase in data retention time of greater than four orders of magnitude while reducing the switching current
* Reduction of read disturb error rate up to five orders of magnitude

These advantages have come without degradation to other performance parameters. The data for the PSC structure indicate significant potential for enabling high-speed applications as well as high-temperature automotive and other applications. Furthermore, since the data shows that the PSC structure’s efficiency gains actually increase as the pMTJ get smaller, the PSC structure opens new pathways to achieving embedded SRAMs in the latest 7nm and 5nm generations.

New MRAM could replace SRAM and DRAM

Spin Transfer Technologies (STT) is developing ST-MRAM technology and products that can replace SRAM (static RAM) and ultimately DRAM (dynamic RAM) in both embedded and stand-alone applications. STT has developed breakthrough technologies in both magnetics and CMOS circuits and architectures that bring ST-MRAM to the next generation. The result: MRAM operating speeds matching those of SRAM cache memories or DRAM — but with far lower cost, no leakage power, and without the endurance and data retention limitations of other ST-MRAM implementations.

Spin Transfer Technologies (STT) believes that its technology holds the potential to enable MRAM to replace not only all embedded non-volatile memories, but also cost-effectively replace SRAM and persistent DRAM.

To do so, MRAM must match or exceed speed, size, power consumption, and endurance specifications as well as the cost structure of SRAM and DRAM. While MRAM has inherently lower power consumption and is non-volatile, today’s solutions meet neither the speed nor endurance of existing SRAM and DRAM products.

STT’s patented technologies are seeking to solve this trade-off:

Differentiated perpendicular magnetic tunnel junction (pMTJ) design and processing
Leveraging its world class magnetics team and state of the art R&D Fab, STT is developing smaller, faster and easier-switching pMTJ structures: the core magnetics technology of MRAM
STT’s own R&D Fab line allows it to accelerate the refinement of the structure

Precessional Spin Current Structure
A proprietary, patented magnetic polarizing structure which significantly increases pMTJ efficiency 40-70% – enabling higher retention with much lower write currents
Has the potential to be used with any pMTJs

The Engine
* A collection of techniques and circuit innovations uniquely tuned to the physics of the pMTJ designed to extend the switching endurance of any pMTJ by up to six orders of magnitude. This benefit requires no changes to the pMTJ
* The Engine leads to smaller write currents (lower power consumption) and smaller base transistors
* The Engine is the culmination of the synergy achieved at STT between magnetic material scientists and circuit and systems engineers

Like the Spin Polarizer, the Engine has the potential to be used with others’ pMTJs