Figure 1: (top) Multi-chip Package, back view of Intel GT3e GPU containing eDRAM and the Intel Haswell processor; (bottom) A stitched image showing the SEM cross-section of the multi-chip package. Click here for larger image. (Source: Techinsights)
Broadwell implemented eDRAM beside the CPU. Though popular for higher performance, it did not seem to hit the cost target. Intel has no plans currently for Skylake eDRAM, to the disappointment of enthusiasts:
I myself have worked in DRAM foundry and I know that 1 transistor and 1 capacitor is always smaller than 6 Transistor SRAM for a given technology node.
So I am not making that mistake at all.
What I am saying is that this eDRAM cell size would correspond to 1x SRAM cell size and the point is that SRAM is taking lot of real estate and is not shrinking well and does not provide enough bandwidth.
So by switching to external DRAM from SRAM, INTEL is having lot of advantage.
Probably IBM came to the same conclusion as Intel and made eDRAM since many years.
@AD2010 by using my elite Googling skills, it appears that Power8 has been available since June 10 2014.
eDRAM cells are much smaller than SRAM cells in the same technology, regardless of Intel, IBM, NEC or whomever is making it. Hopefully you aren't under the misapprehension that Intel is the first IDM to make DRAM cells smaller than SRAM.
IBM latest eDRAM is 22 nm on SOI with trench technology (for instance on POWER 8). This doesn't mean that the half pitch on the eDRAM macro is 22 nm , but the logic besides the eDRAM macro on the same chip is a 22 nm technology.
Yes IBM was a pioneer in eDRAM and particularly TRENCH capacitor technology, which was later used by Infineon-Qimonda. I do not know who has older patents on eDRAM, is it IBM or INTEL? And MIM Capacitor can be formed regardless of capacitor frame structure (stack or trench).
Regarding this eDRAM device from Intel, the concept of using stacked capacitors is not new, also the idea of placing the stacked capacitor between the interconnects is not novel;
however, we are forgetting the most interesting point in this device and that is the eDRAM cell size is way smaller than the most advanced SRAM cell and there is plenty of room to extend the memory size without changing the technology node. Also Intel claims very good retention properties of this device, which they attribute to the trigate structure of the access transistors.
I am sure Power 8 processor of IBM with 22 nm node process would be a milestone in technology but I do not know if this product is already available in the market?
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