Through the optimisation of silicon nanocrystal properties, Freescale Semiconductor (distributed by Farnell InOne ) reports it has manufactured the world’s first 24 Mbit memory array based on silicon nanocrystals.
The company said this non-volatile memory technology is denser, faster and more cost-effective than conventional Flash.
As the industry begins manufacturing at smaller geometries, embedding floating gate-based Flash becomes difficult to produce cost-effectively, Freescale noted.
At small dimensions, the chip area consumed by the 9 to 12 V transistors required to write and erase conventional Flash module can’t be scaled down, and voltages can’t be reduced without risking memory failures.
Silicon nanocrystal memories are part of a class called thin-film storage that are more scaleable than conventional Flash, as their tunnel oxide thickness can be reduced without impacting reliability.
The charge is stored on isolated nanocrystals and is lost only from those few nanocrystals that align with defects in the tunnel oxide - while the same defects would result in significant charge loss from conventional Flash.
A thinner tunnel oxide permits lower-voltage operation, substantially reducing memory module area needed to generate the bit-cell programming voltages, and manufacturing cost reductions.
The combination of higher bit density and reduced cost translates to lower cost-per-bit embed memories. Freescale said it expects significant reductions in cost-per-bit of silicon nanocrystal thin-film storage memories.