A cross section of the embedded-PCM bitcell integrated in the 28 nm FD-SOI technology shows the heater that quickly flips storage cells between crystalline and amorphous states.
Fully Depleted Silicon On Insulator, or FD-SOI, another technology that ST pioneered, is a planar process technology that delivers the benefits of reduced silicon geometries while actually simplifying manufacturing. Combining 28 nm FD-SOI and PCM enables memory array sizes that are 4-5 times larger than what Flash on bulk 40 nm CMOS can achieve.
ST’s PCM technology has been developed and tested to operate within the most stringent automotive requirements for robust high-temperature operation, radiation hardening, and data retention.
PCM achieves automotive requirements for AEC-Q100 Grade 0 with an operating temperature up to +165°C.
With single-bit alterability, PCM technology delivers significantly better write and comparable read performance than flash-based memories that require at least a byte- or sector-erase cycle before reprogramming. This single-bit alterability simplifies software handling of data storage. ST’s implementation benefits from patented technology related to the memory cell and to the GST alloy to support high-temperature data retention, including during solder reflow, so firmware can be uploaded to PCM before mounting and soldering.
PCM is a back-end technology which separates the non-volatile memory-cell process module from the complex logic-transistor modules built in the Front-End.
As a back-end, metallization-based process, PCM is technology-independent, so it can be embedded in virtually any technology node.
The speed/power characteristics of the PCM macro-cell and its roadmap at smaller geometries offer a scalable solution for large embedded memories.
Ever more demanding applications are pushing the limits of MCU architectures due to their need for more processing power, lower power consumption, and larger memory sizes. One of the most challenging demands is for larger embedded memories to hold bigger and more complex firmware.
PCM presents a solution to these chip- and system-level challenges, while meeting automotive requirements for AEC-Q100 Grade 0, operating at temperature up to +165°C. In addition, ST’s technology assures firmware/data retention through high-temperature soldering reflow processes and immunity to radiation, for additional data safety.