Supplier of advanced semiconductor solutions, Renesas Electronics, has announced that it has successfully confirmed large-scale memory operation in a split-gate metal-oxide nitride oxide silicon (SG-MONOS) process using fin-shaped 3D transistors for use in microcontrollers (MCUs) with on-chip flash memory having a circuit linewidth of 16 to 14nm or finer.
This result follows Renesas’ achievement in December 2016, when it announced its confirmation of operation for what it claims to be the industry’s first SG-MONOS flash memory cells that use fin-shaped transistors. Renesas has demonstrated the operation and reliability of large-scale memory, achieving significant progress towards realising large-capacity flash memories of more than 100MB for use in MCUs of the 16 to 14nm and later generations.
Advances in vehicles especially the autonomous-driving vehicle and progress in the smart society connected by the IoT are accelerating, creating upsurge in demand for advanced high-performance MCUs that make use of even finer design rules to achieve higher performance and lower power consumption. To address this demand, Renesas is developing flash memory that can be embedded in the 16/14nm process generation, which succeeds the 40/28nm processes in which MCUs are currently either being mass produced in or are being developed for. Renesas is now working to achieve further advancement of MCUs by combining high-performance/low-power logic with large-capacity/high-performance nonvolatile memory implemented with finer feature sizes.
In 2016, Renesas announced the successful development of the industry's first fin-type SG-MONOS flash memory cell by applying and adopting charge trap type flash memory technology that had been used in the past. The SG-MONOS flash memory performs its data storage in a thin trap film formed on the surface of the silicon substrate, which makes it comparatively easier to deploy it in a fin structure with a three-dimensional structure. Another feature is that it is highly compatible with 16/14nm logic processes that have the same fin structure. Also, the superlative charge retention characteristics, which are a feature of charge trap type MONOS flash memory, are not degraded even when the fin structure is introduced, and Renesas has verified that the same reliability characteristics as existing devices can be achieved.
The challenge when incorporating this fin structure SG-MONOS flash memory cell in a 16/14nm generation MCU is the increase in sample-to-sample variations associated with increasing the memory capacity. Renesas succeeded in overcoming this issue and verified its operation even in a large-scale memory, which marks a significant advancement towards the achievement of high-performance, high-reliability MCUs that include an embedded flash memory system in the 100MB class.
Renesas was able to demonstrate the following aspects of the large-scale embedded flash memory developed in this effort.
The result represents a significant progress towards the achievement of high-performance MCUs that have four or more times the processing capacity of 28nm generation devices and that includes memory capacities in excess of 100MB for the 16/14nm generation and beyond, using SG-MONOS structure flash memory.
Currently, Renesas mass produces MCUs fabricated in a 40nm generation process using SG-MONOS structure flash memory and is also developing 28nm generation MCUs. Based on the demonstration of large-scale memory operation, Renesas plans to develop 16/14nm generation MCUs with a target of 2023 for practical applications and is committed to continuing to contribute to progress in the automotive field and the achievement of a smart society.