Renesas Electronics has introduced its split-gate metal-oxide nitride oxide silicon (SG-MONOS) FinFET flash memory for embedded devices with 16nm/14nm circuit linewidth.

Advances in advanced driver assistance systems (ADAS) and the Internet of Things (IoT) have created demand for microcontrollers(MCUs) fabricated using finer process technology. To address this demand, Renesas has developed embedded flash memories for automotive MCUs based on 16nm/14nm process technology. At 16nm/14nm, fin-field effect transistors (FinFETs) can be used to reduce power consumption to overcome scaling limits of planar transistors.

Employing a FinFET for embedded flash memory can be challenging, however, depending on the structure of the flash memory, said Renesas. Two types of embedded flash memories have been proposed and implemented: the floating-gate and the charge trap. According to Renesas, the charge trap flash memory has better charge retention characteristics and reliability in automotive MCUs, compared with floating-gate memory. Also, as the memory functional material is formed on the surface of the silicon substrate, they are easy to be extended into a three-dimensional fin structure. In contrast, floating-gate flash memory cells have a complex structure, which is difficult to integrate into a fin structure.

Another advantage of SG-MONOS over the floating-gate structure is that the memory cell structure is maintained after replacing a dummy polysilicon gate electrode with the metal gate electrode. This is the process used to manufacture logic CMOS devices with high dielectric gate insulators and metal gate electrodes.