Like all the big memory companies, Micron invests a lot of time, money and resources into R&D pushing existing technology and developing ‘what comes next’ technology. Micron have a reputation for being at the forefront and, while not much is openly disclosed (in the scientific literature, for example), the Silicon Valley rumor mill is always alive with the latest guesses as to where Micron will move next. Recently through their purchase of Numonyx they have been at the forefront of bringing PCM (phase change) to market, initially at least, as a NOR Flash replacement. As to they other endeavors in emerging memory technologies, some limited information is available in Analyst Conference presentations but it is fairly high level and gives no direct indication of their actual focus.
The information has often been presented in the form of ‘traffic light’ charts where key technology attributes are graded from green (good) to red (extreme, i.e. needs work). An example from Winter (February) 2011 is shown above. Interpreting the various acronyms requires a bit of digging but I believe MVO is broadly what is covered by ReRAM, technologically speaking**. (Any identification of PCMS would be most welcome**). The last such update I have found is from the Fall (October) 2012 Analyst Conference (link and scroll down) where PCM (presumably because it has emerged) and PCMS have gone and FBRAM (Floating Body RAM, IP acquired from Innovative Silicon, ISI)** has appeared. Looking at the changes in the traffic lights is interesting. For example, Molecular and MRAM are unchanged, while CBRAM and STT-RAM show improvement. FeRAM and MVO seem to have made some steps forward and some steps back! I’ve summarized these trends in a traffic light plot of my own. The first column lists the various emerging technologies with a color corresponding to an average of Micron’s grading of the five technology attributes. The other two columns are similarly coded but in terms of the change (deltas) over the last 6 months (middle column) and 1 year (third column). Thus CBRAM and STT-RAM have ‘green’ entries in columns 2&3 representing their perceived improvement, i.e. coming closer to being ready for production.
One should take this analysis with at least a couple of grains of salt but I think one can say the following:
* None of these technologies will become a Micron product if any of the ‘traffic lights’ is red. A yellow or two may be ok but orange or red must be eliminated.
* Micron are just observing what others are doing in the Molecular and MRAM areas. (No progress and the assessment is bleak).
* FBRAM is something they have just started looking into and given the TEM picture in the Analyst presentation, perhaps a few lots have been run in a Micron Development fab.
* Not sure what to make of Micron’s interest in FeRAM. Seems there is progress but no TEMs!
* MVO is obviously giving Micron problems particularly in terms of manufacturability, endurance and retention. Nonetheless, they would appear to be processing wafers.
* CBRAM and STT-RAM would appear to be being actively developed with progress being achieved. CBRAM has already reached the no ‘red or orange’ level….
Christie Marrian ReRAM-Forum Moderator
** Thanks to some alert readers I’ve been able to clarify some of the acronyms. See Comments below