ST announced that it was sampling the MCUs, made using the company's 28nm fully-depleted silicon-on-insulator (FDSOI) technology in May 2018 (see ST samples MCU with embedded phase-change memory ). It has now provided initial performance benchmarks of ePCM at IEDM 2018 and full automotive qualification for MCUs expected in 2020.
The design makes use of the reverse body bias available with 28FDSOI and has a triple-gate high-k metal gate architecture. A 5V transistor has been presented and 16Mbyte array is used to measure the bit-error rate at 10^-8.
ST said microcontrollers with ePCM would target powertrain systems, advanced and secure gateways, safety/ADAS applications, and vehicle electrification. The technology can meet the requirements for AEC-Q100 Grade 0, operating at temperature up to +165°C. In addition, the technology provides firmware/data retention through high-temperature soldering reflow processes plus a high degree of immunity to radiation.
PCM is conventionally made using a mix germanium antimony tellurium (GST) alloy and operates on the transition between a high-resistance amorphous state (logic 0) and low resistance crystalline state (logic 1). It shows better scalability than flash memory but during many years of research has proved susceptible to thermal cross-talk. However, it is thought that high temperature immunity may be enhanced through the development of specific GST mixes.
PCM also allows single-bit alterability, which simplifies software handling of data storage, when compared to flash-based memories that require byte- or sector-erase before reprogramming.
"Having applied ST's process, design, technology, and application expertise to ePCM, we've developed an innovative recipe that makes ST the very first to combine this non-volatile memory with 28nm FDSOI for high-performance, low-power automotive microcontrollers," said Marco Monti, president of the automotive and discrete product group at ST, in a statement. "With samples already in some lead-customers’ hands, we’re confirming the outstanding temperature performance of ePCM and its ability to meet all automotive standards, further assuring our confidence in its market adoption and success."