Samsung is shipping phase-change memory in a multi-chip package (MCP) as a NOR replacement for mobile phones.

Phase-change memory involves storing binary digits as different levels of resistance caused by phase changes in an alloy of germanium, antimony and titanium. The phase changes from amorphous to crystalline and back again.

The firm calls its phase-change product PRAM (Programmable RAM) and it combines the non-volatile nature of flash memory with the high-speed capability of DRAM. That's high-speed compared to flash, rather than modern DRAM.

NOR memory is pretty slow compared to Samsung's 60nm PRAM, which is claimed to provide three-times faster data storage performance per word than NOR chips.

Samsung's PRAM is 512Mbits and is backwards-compatible with 40nm-class NOR flash memory in both its hardware and software functionality.

Dong-soo Jun, Samsung Electronics' EVP for Memory Sales and Marketing, said: "Our PRAM MCP will not only enable handset designers to utilise conventional platforms, but expedite the introduction of LPDDR2 DRAM and next-generation PRAM technology as the leading-edge basis for high-performance solutions."

Numonyx, which is being bought by Micron, is the other main phase-change memory developer. It recently announced a 90nm process, 128Mbit product. Samsung expects to move to a 30nm process some time in the near future, and then progress beyond that.

The firm expects PRAM to be widely embraced by next year as the successor to NOR flash in consumer electronics designs, and to become a major memory technology. Samsung is continuing development of faster PRAM write speeds, seeing that as essential for spreading PRAM's market scope into product classes such as MP3 players, personal multimedia players, navigational devices, solid state drives and HDTVs.

It is also hoped by phase-change memory developers that it will succeed NAND flash, which stops being viable once the process size gets down below the 20nm level. The precise cross-over point is not known. HP has its competing Memristor technology, but this is still in development and HP is probably looking for a partner to take the technology and fabricate chips using it.

This is likely to be a multi-year effort and Memristor products will come to a market, if they come, in 2013 or later. By then phase-change memory chips could be shipping in some volume from two competing suppliers. This will give HP and its potential partner a pricing problem unless they have an overwhelming performance advantage. ®