History of Memory Slideshow in EE Times

EE TimesEE Times has published a very interesting slideshow called: A Brief History of Memory by Kristin Lewotsky.  This is recommended reading for all who peruse of The Memory Guy blog.  Even the comments are good reading, with one commenter sharing a history of ferroelectrics that dates back to the 1950s.

It’s interesting to see the Continue reading “History of Memory Slideshow in EE Times”

Everspin Samples First STT MRAM

Everspin today announced that select customers have been sampled the world’s first “ST-RAM” a 64Mb chip using STT MRAM technology, rather than Everspin’s existing production toggle MRAM technology.

For the past decade or so memory researchers have been looking to Spin Transfer Torque (sometimes called “Spin Torque Transfer”) MRAMs as a way of getting to tighter processes than conventional toggle MRAM.  It seems that current densities in toggle MRAM rise too high as the process shrinks – at some point the process could no longer scale since chips would burn themselves out during programming.  The ST-RAM paves Everspin’s path toward Continue reading “Everspin Samples First STT MRAM”

Adesto Acquires Atmel’s Serial NOR Business

Atmel Sells Serial Flash Business to AdestoIt’s not often that a small private firm acquires a part of a larger public firm, but that’s what happened today with Atmel and Adesto.  Adesto, a manufacturer of alternative memory technology, has purchased Atmel’s serial NOR flash business for an undisclosed sum.

The transaction covers the Atmel “Data Flash” and “BIOS Flash” product families and the employees supporting those products.  Atmel has retained its Serial EEPROM, Crypto and Digital Temperature Sensor memory product lines and plans to continue to invest in those businesses.

This is not a small thing.  Serial NOR now accounts for roughly Continue reading “Adesto Acquires Atmel’s Serial NOR Business”

Alternative Memory Technologies Patiently Wait For Market to Explode

Cross Section of a PCM Bit CellLane Mason of Objective Analysis recently shared with The Memory Guy an article he wrote for the 4 April 2007 Denali Memory Report covering Phase Change Memory (PCM or PRAM.)  It looked like something big was about to happen with the technology: PCM looked nearly ready to enter production.

The article included an excerpt of an EE Times interview with Micron’s CEO, the late Steve Appleton, in which Appleton stated that PCM advocates threatened to take over the memory market in 2000.

Here it is 2012, and PCM represents little more than a drop in the bucket when it comes to memory sales, although Continue reading “Alternative Memory Technologies Patiently Wait For Market to Explode”

Micron PCM Enters Mass Production

Cover of Electronics Magazine, 28 September, 1970, with Intel PCM articleAfter years of prototyping Micron Technology claims to be the first to introduce production volumes of Phase-Change Memory, or PCM.  This memory, also known as PRAM, has long been positioned as a contender to replace flash once flash reaches its scaling limit.  Rather than use electrons to store a bit, PCM uses a type of glass that is conductive when in a crystalline state and resistive when amorphous, two states that are relatively easy to control.  The size of the bits can shrink to a very small dimensions, allowing PCM to scale into the single-digit number of nanometers, which most folks today believe to be beyond the realm of flash.

This product began its life at Intel, then followed the Numonyx spin-off, and was taken over by Micron when it acquired Numonyx.  In fact, Intel got into PCM very early on – this post’s graphic is the cover of an Electronics Magazine from September 1970 with an Intel story, written by Gordon Moore, telling about a 128-bit PCM research chip.

So far only three companies have produced samples Continue reading “Micron PCM Enters Mass Production”

A New Way to Build Phase-Change Memory (PCM)

The University of Pennsylvania CrestAn acquaintance recently brought to my attention an article in R&D Magazine about some pioneering research on phase-change memories or PCM.  The researchers’ findings hold a lot of promise.  (R&D Magazine’s article is based upon an original paper in the journal Science.)

A team led by Ritesh Agarwal, associate professor at the University of Pennsylvania, was trying to develop a better understanding of the mechanism behind the phase changes in PCM.  The team found that existing programming algorithms that involve melting the material could be replaced with pulses of electrical current that not only would program the cell without heat, but provided an “On” to “Off” resistance ratio of 2-3 orders of magnitude, which renders the cell significantly easier to read, especially in the presence of noise.  This effectively makes memory chip design Continue reading “A New Way to Build Phase-Change Memory (PCM)”

The End of Flash Scaling

The End is at Hand for NAND Flash ScalingEveryone knows that flash memory is about to hit its scaling limit – it’s right around the corner.  We’re ready for it because it’s been right around the corner for more than a decade now.  It’s so close we can taste it.

When will it happen?

One thing that is quite clear is that nobody knows when NAND flash will stop scaling.  Everyone knows that it’s soon, but researchers continue to find ways to push the technology another couple of process nodes past where anyone thought it could possibly go, and they have been doing this since Continue reading “The End of Flash Scaling”

Remembering Core Memory

Ryszard Milewicz' photo of Core MemoryNostalgia buffs who lived through computing in the 1970s will enjoy some magnificent photos shared in a blog post by Ryszard Milewicz.  These photos give three views of a ferrite core memory plane.  The photo from this blog is a part of one of Mr. Milewicz’ close-up photos.

For those who were not exposed to core memory, this technology was based upon an approach in which every individual bit of a computer’s memory was a tiny donut made of compressed iron powder (“Ferrite”) that had to be hand strung with copper wire into a plane of bits.

A co-worker of The Memory Guy once had a high-speed core memory array that he used as Continue reading “Remembering Core Memory”

IEEE Spectrum: Did Bad Memory Chips Down Russia’s Mars Probe?

Radiation SymbolThe IEEE Spectrum published an interesting article postulating that Russia’s recently-failed Mars probe may have suffered from bad memory chips.  According to the Spectrum article the Russian government’s Official Accident Investigation Results faulted SRAMs:

The report blames the loss of the probe on memory chips that became fatally damaged by cosmic rays.

Both the main computer and the backup computer seem to have failed at the same time, Continue reading “IEEE Spectrum: Did Bad Memory Chips Down Russia’s Mars Probe?”

How Do You Make a ReRAM Work?

I/V Curve for Panasonic's ReRAM Select DiodeDuring this week’s International Solid State Circuits Conference (ISSCC) I learned some very valuable information about memories built using crosspoint matrices.

Since ISSCC is a conference at which you meet the best and brightest minds in the industry it should come as no surprise that I was able to meet with several of the most forward-thinking industry luminaries.  One of them explained to me a very fundamental difficulty with resistive RAMs (ReRAMs): These devices require a forward current to be programmed to a “1” and a reverse current to be set to a zero.  This goes against the ideal crosspoint memory design in which a bit would consist of nothing more than a diode in series with a memory element.  By inserting a diode, the current can only run in one direction, so a bit can be programmed or it can be erased, but not both.  This is called Continue reading “How Do You Make a ReRAM Work?”