“We’ve taped out a 1Gbit phase change device on 45nm”, said Doller. He conceded that the density level is “well below floating gate” densities, which are currently at 16Gbit, but added that the next generation of process technology, which Numonyx will be on next year, will deliver a 4Gbit to 8Gbit memory.
That, of course, could change if Numonyx masters multi-bit per cell technology. At last year’s ISSCC, Numonyx demonstrated a 2bit-per-cell phase change memory but, said Doller: “The key thing is to implement it with the same performance as single bit per cell.” And that cannot, yet, be achieved. Doller declined to say when he expects the problem to be solved.
Phase change represents Numonyx’s future because it is thought that floating gate technology will start to become impractical at 32nm.
“Our view is that it’s scalable for NOR to the 32nm node”, said Doller.
Asked if he thought that Spansion’s Mirrobit could be scaled further than that, Doller replied: “Floating gate and Mirrorbit will run out about the same time. Fundamentally it’s about how the devices programme.”
On the other hand, phase change has about five generations to run. “IBM’s research labs have produce chalcogenide cells with 5nm features”, said Doller, “they have determined that the technology will work at 5nm.”
Numonyx, whose name was widely assumed to be derived from Ovonics Unified Memory the technology pioneered by Stanford Ovshinsky, has been selling 128Mbit phase change memories for a year.
“We sold our first phase change parts for revenue last year,” said Doller, we’re working with over 20 customers who have had samples. Phase change is good for some applications.”
Like which ones? “Like in servers to replace DRAM”, replied Doller.
Yesterday Numonyx announced what could be its penultimate generation of floating gate flash chips, a 1Gbit MLC NOR device made in 45nm technology which is being made in its Israel fab, the old Intel Fab 18. The chips are being sampled now and will move into volume production next year, first for wireless customers, then for general customers.
The 45nm NOR memory uses a self-aligned contact approach which allows the continued scaling while maintaining backward compatibility.
So the 45nm NOR chips are drop-in compatible with Numonyx’s 65nm NOR flash chips which allows cellular OEMs to reduce development costs, extend the life of current platforms, and bring new products to market faster.
“Numonyx engineers overcame major scaling limitations by developing new process techniques to produce the 7th generation MLC NOR flash on the industry’s most advanced 45nm technology,” said Doller.