
Microsemi Licenses Crossbar ReRAM Non-Volatile Memory - rbanffy
https://www.anandtech.com/show/12758/microsemi-licenses-crossbar-reram-nonvolatile-memory
======
dsr_
For those who are confused: "1x nm" means a number between 10 and 19nm, not
"one times a variable nanometers".

I was confused for a bit.

~~~
kurthr
Hah, yeah that wasn't a substitution I'd seen before. They really should have
just called out Fin-FET process compatibility since all of those are below
20nm.

~~~
wtallis
1x, 1y, and 1z nomenclature is standard in the memory industry, where the
foundries are less keen on giving out hard numbers about their manufacturing
processes than the logic fabs are.

FinFETs don't have anything to do with ReRAM (or MRAM), since the memory is a
back-end construction. When designing the memory, you don't have to care about
whether the underlying transistors are planar or FinFET, you just need to know
whether the memory can scale down to the same pitch. There will be 12nm planar
FD-SOI chips taping out next year at GloFo, so 1x nm for a logic process
doesn't imply FinFETs, and FinFETs aren't all smaller than 20nm.

------
kurthr
To be clear these (Resistive RAM and Magnetic RAM) are really competitors to
Flash (EPROM) rather than DRAM or 3D XPoint from Intel. Their main advantages
are process simplification (Flash requires a LOT of extra layers) and cost
rather than speed. In the industry people are very careful with new Non-
volatile memories, because the failures may have long (delayed) failure modes
that cause horrible problems and liability.

I'm fairly positive on these two choices (Re&M-RAM) mostly because people have
learned to be fairly sceptical and require a lot of testing and they are
porting to mulitiple Fabs. Even with the license it will be at least 12 months
before there could be customer samples from the first licensee, Microsemi.

~~~
wtallis
MRAM has so far been primarily a competitor to SRAM and NOR flash, but
definitely not to NAND flash. ReRAM as an embedded memory will be competing in
a similar space, but as a discrete memory will probably be most comparable to
3D XPoint.

~~~
bpye
I assume MRAM and FRAM refer to the same thing? If so Texas Instruments have
some pretty cool (I think) microcontrollers using FRAM allowing for a user
defined spit between volatile and non vatime memory, the MSP430FRxx series, I
don't think they have it in any ARM parts though.

~~~
wtallis
No, FRAM is quite different from MRAM. A FRAM cell has a single ferroelectric
element that is read destructively (just like magnetic core memory). A MRAM
cell has a pair of magnetic elements and resistance through one of them varies
depending on whether the magnetization is aligned with the other element. That
resistance is measured non-destructively.

