At this year’s ISSCC, there was no update from the Micron/Sony collaboration which had presented a 27nm technology 16Gb Cu CBRAM chip last year. However, there are some tantalizing titbits in their latest (2015) Winter Analyst Conference presentation. As in the 2014 Winter Analyst Conference presentation, there is a clear roadmap showing a Roadmap which includes a ‘New Memory’ ramping to ‘volume capability’. Some things have changed, notably the title, in 2015 it is an ‘Innovation Roadmap’ as opposed to 2014’s ‘Memory Technology Timelines’, the colour scheme is a less jarring and Micron have gone for rectangular milestones this year rather than circular. However, the date for a ‘New Memory A’ being at ‘volume capability has not shifted from mid 2015 although the fine print qualifies this with ‘…position for ramp in 2016’ whereas last year it was ‘…position for ramp in 2015’. So I guess Micron are having it both ways, no change in the schedule for capability but a one year push-out for the manufacturing ramp.
Other highlights are the confirmation that Micron will shift from planar to 3D NAND in 2015 with a 32 layer product and no plans for a sub 16nm planar NAND. In addition, ‘New Memory B’ is still planned for 2017 although ‘New Memory A Gen2’ has disappeared from the roadmap.
There are a couple of clues as to what is ‘New Memory A’ might be as it is not explicitly identified. A couple of images are recognizable as being from the Micron/Sony 27nm 16Gb ‘RRAM’ (CBRAM) chip (see the cell image to the left, for example) although they are not acknowledged as such. There is also an SEM micrograph of labelled ‘STTRAM Array’ although it is not a cross-section. However, just to keep us all guessing, Micron indicate they continue to invest in ‘other … future memory core technologies’. So my guess is that we will see the Sony/Micron CBRAM chip ramping in 2016 followed by STTRAM as ‘New Memory B’.
Interestingly there is a slide included in the Summer 2014 presentation not included in the 2015 Winter Analyst presentation. This gives some insight into where Micron see two different new memories placed in the DRAM/NAND space. See image below. One new memory is clearly cost focussed (ReRAM?) whereas the other is performance focussed (STTRAM?). However, the ‘performance focussed’ technology is described as having a volatility only marginally better than DRAM…. See figure below.
So the bottom line is that Micron seem clearly committed to achieving a volume capability and presumably sampling of some form of ReRAM/CBRAM (my guess) and 32 layer 3D NAND in 2015, i.e. this year…
Christie Marrian, ReRAM Forum Director
p.s. Stop press: Intel/Micron’s 3D NAND is reported as sampling and the good folks at Anandtech have already made some comparisons with Samsung’s V-NAND.