Advanced Micro Devices is rightly admired for its smart decisions, such as putting a memory controller on board the Opteron MPUs and tying up with IBM Corp. to do joint process development in Fishkill, N.Y.
Now, AMD faces key decisions about its memory technology. Embedded DRAM, 3D integration, and floating body (FB) memory, are the main candidates. AMD could license the SOI eDRAM technology from IBM: Big Blue says it will have the SOI eDRAM technology ready for its own Power series MPUs at the 45-nm node.
An AMD spokesman said “as part of our ongoing R&D partnership with IBM we are evaluating a number of emerging technologies including eDRAM. We also have previously announced that we are working on a dense cache technology called ZRAM with Innovative Silicon Inc (ISI).”
The floating body memory which ISI is developing leverages the history effect of SOI to store the bit, requiring only one control transistor, providing advantages in density and cost. However, as scaling proceeds, the question becomes whether there is enough stored charge to make a reliable FB memory.
IBM’s director of 45-nm technology Subramanian Iyer said IBM has studied the floating body memory approach “very carefully,” but concluded that the approach is overly sensitive to threshold voltage variations. (Renesas Technology, at last summer’s Symposium on VLSI Technology, proposed that a reference voltage cell be added to deal with variability, but that twin-cell FB approach brings in extra complexity.)
The 3D memory approach requires matching a logic slice with a memory array, connected by tens of thousands of vertical studs only a few microns in length. For the high bandwidth and densities needed for video processing, 3D integration offers compelling advantages. AMD is "well down the road toward a 3D solution," one knowledgeable source said, but the challenge is to get the design and manufacturing infrastructure ready for the day when SRAM runs out of steam.
About weQuest: weQuest's are written by G Dan Hutcheson, his career spans more than thirty years, in which he became a well-known as a visionary for helping companies make businesses out of technology. This includes hundreds of successful programs involving product development, positioning, and launch in Semiconductor, Technology, Medicine, Energy, Business, High Tech, Enviorntment, Electronics, healthcare and Business devisions.