LONDON — Non-volatile memory supplier Numonyx BV (Geneva, Switzerland) has started the commercial supply of its 'Alverstone' 128-Mbit phase-change memory to selected customers in the embedded sector, the company said Friday (Dec. 19).

Alverstone, a non-volatile phase-change memory implemented in 90-nm CMOS, began sampling in February 2008 although it was already coming out later than previously intended. Intel and STMicroelectronics, who had shared R&D on the technology before pooling their flash memory interests to form Numonyx, later said they had delayed the introduction to make specific improvements to the design.

"In February we said we would be in production in 2008 and we did it," said Glen Hawk, vice president and general manager of the embedded business group at Numonyx.

The idea of a dense memory with high cycling endurance that retains data when power is removed has been a goal since before the days of the dynamic RAM. The phase-change approach to a solid-state device has been a long time coming to market having been researched by Stanford Ovshinsky at Energy Conversion Devices Inc. in the 1960s.

In Numonyx case the memory is direct descendent of the Ovshinksy research and is based on a thermally-induced reversible change in a chalcogenide material — between an amorphous and crystalline state. The 128-Mbit device has been designed as a pin-compatible NOR replacement that provides fast read and write speeds at lower power than conventional flash, and allows for the bit alterability normally seen in RAM.

Numonyx, and Intel before it, have always stressed the purpose of the 90-nm memory as educational vehicle, necessary because of the different nature of phase-change memory. In April 2008 the company said it would skip the 65-nm generation and expected to be in production on a 45-nm process by mid-2009.