About Semiconductor Device Group
To realize the Society 5.0, high-performance semiconductor devices with low power consumption are essential, not only for digital infrastructure such as IoT, AI, and big data, but also for high-efficiency power electronics. We aim to develop innovative devices by focusing on the physics of interfaces between insulating films, metals, and semiconductors, which determine the performance and reliability of semiconductor devices, and by establishing guidelines for material design and interface control.
Specialized Research Field
Gate Stack Technology for Beyond 1nm CMOS
The CMOS integrated circuits, fundamentals of information and communication devices such as smartphones and computers, have been evolving since mass production began in the 1970s through the introduction of various process technologies and new materials. Currently, a chip of about 1 cm2 contains tens of billions of MOS (Metal-Oxide-Semiconductor) transistors, each smaller than an influenza virus. Silicon (Si) has long been used as the semiconductor material, but its performance limitations are approaching, and in the next ten years, semiconductor materials that can replace Si will be indispensable. Candidates for these materials include transition metal dichalcogenide two-dimensional materials and nanosheet of germanium (Ge). For these semiconductors to perform as MOS transistors, it is crucial to determine which insulating films and metals to combine with and what processes to apply. This is because the interfaces in the MOS gate stack, composed of metal, insulating film, and semiconductor, significantly affect current drivability (mobility), threshold voltage control, and long-term reliability.
We are working on deepening device physics and process technology through the prototyping and evaluation of MOS transistors and the physical analysis of interface structures.
Wide Bandgap Semiconductor Power Device
In power semiconductors, which are responsible for the electric power conversion and control, the replacement of MOS transistors used in electric vehicles (xEVs), railway inverters, and power conditioners for solar and wind power generation from silicon (Si) to silicon carbide (SiC) is progressing. However, SiC MOS transistors have not yet fully realized their potential, and one of the reasons is the SiO2/SiC interface.
To improve the performance of SiC MOS transistors, we are working on elucidating the physical properties of the SiO2/SiC interface and developing novel gate oxide formation processes.
Group Members
