Don Dingee
Moderator
We've been debating the need and ability to scale embedded flash to 28nm and below.
Renesas is working on it, announcing a new implementation of SG-MONOS eFlash moving from 40nm to 28nm. There are more than a few problems involved:
Random read speeds have been increased to 200 MHz on 4MB chip prototypes at 28nm, for a peak read throughput of 6.4GB/sec.
The initial figures at 28nm suggest almost twice the performance improvement over 40nm, with similar reliability.
It's an interesting development. Renesas often announces forward-looking technology research for MCUs that may be a couple years ahead of actual product.
Press release:
Renesas Electronics Develops 28nm Embedded Flash Memory Technology that Realizes Even Faster Read and Rewrite Speeds for Automotive Microcontrollers
Renesas is working on it, announcing a new implementation of SG-MONOS eFlash moving from 40nm to 28nm. There are more than a few problems involved:
- Reducing cell size reduces cell current, and overdrive could affect gate oxide reliability at high temp, overcome with negative temp dependence overdrive.
- High-voltage stress during erase can hurt reliability, so erase speeds are controlled to avoid maximum erase voltages in high erase speeds.
- High-speed writes of 2.0 MB/sec were achieved with negative back bias and paralleling flash macros.
- Spread-spectrum clock generation on the drive clock for charge pumps reduces noise.
Random read speeds have been increased to 200 MHz on 4MB chip prototypes at 28nm, for a peak read throughput of 6.4GB/sec.
The initial figures at 28nm suggest almost twice the performance improvement over 40nm, with similar reliability.
It's an interesting development. Renesas often announces forward-looking technology research for MCUs that may be a couple years ahead of actual product.
Press release:
Renesas Electronics Develops 28nm Embedded Flash Memory Technology that Realizes Even Faster Read and Rewrite Speeds for Automotive Microcontrollers