Superconducting Technology Assessment - nitrd

4MB MRAM BIT CELL: 1 MTJ & 1 TRANSLATOR
Sense path electrically isolated from program path
Figure 3.2-3. Diagram of FS-TMR cell (Courtesy of J. Slaughter, Freescale Semiconductor)
In practice, a relatively small increase in MR can significantly improve read-performance and, thus, memory access.
As a result, research is focused on higher MR materials. Recent publications have reported that MgO has four-times
higher MR than the present AlOx tunnel barrier in TMR cells. Sub-ns memory access is expected, especially at
cryogenic temperatures, from continuing improvements in control of thin film micromagnetics. In contrast, write
times below 500 ps are unlikely at any temperature in TMR devices, since they are limited by the fundamental
Larmor frequency and bit-to-bit variability. Extrapolating performance of TMR FS-MRAM to cryogenic temperatures
appears promising.
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