***The following content was written by the author of the paper with URA.***
The research group at Kanazawa University, including Professor Norio Tokuda from Nanomaterials Research Institute and Kazuki Kobayashi from Graduate School of Natural Science and Technology, in collaboration with Toshihaaru Makino, Team Leader from Advanced Power Electronics Research Center, The National Institute of Advanced Industrial Science and Technology (AIST), and Dr. Christoph E. Nebel, CEO of Diamond and Carbon Applications GmbH, Germany and Invited Professor at Kanazawa University, succeeded in fabricating a diamond MOSFET(*1) with an atomically flat diamond surface at the MOS interface(*2).
Since wide bandgap semiconductors are capable of highly efficient power control, they are thought to be a type of next-generation power device suitable for achieving carbon neutrality. Diamond, with its particularly high breakdown electric field, carrier mobility, and thermal conductivity, is proposed to be an ideal material for semiconductor devices.
In 2016, Professor Tokuda and his group succeeded in developing the world’s first inversion channel diamond MOSFET by improving their own diamond growth and surface/interface control technologies. However, they found that channel scattering at the MOS interface increased resistance during operation. This time they succeeded in fabricating the world's first diamond MOSFET with an atomically flat diamond surface at the MOS interface, using a selective buried growth technology they had developed in 2022. This breakthrough has been shown to significantly enhance the performance of diamond MOSFETs.
Further advancements of this technology will represent a significant step toward the practical application of diamond-based semiconductor devices.
The results of this research were published ahead of print in the online edition of Elsevier's international journal Carbon on January 28, 2025.
Figure 1:(a) Schematic and (b) optical microscopy image of the inversion channel diamond MOSFET developed this time with an atomically flat interface.
(🄫Kobayashi et al.,Carbon, 2025)
Figure 2. Drain current density (Id) - drain voltage (Vds) characteristics of MOSFETs fabricated in 2016 and in this study.
Note that the solid lines are measured values and the dotted lines are estimated values.
【Glossary】
*1： MOSFET
MOSFET stands for Metal Oxide Semiconductor Field Effect Transistor and refers to a field effect transistor with an interface comprising a metal, an oxide film and a semiconductor. The basic structure of most semiconductor devices in widespread use today is the inverted-layer-channel MOSFET.
*2： MOS interface
MOS stands for Metal Oxide Semiconductor and refers to the interface between the oxide film and the semiconductor; it is where the channel of the MOSFET is formed and is determined by the integrity of the MOS interface.
Click here to see the press release【Japanese only】
Journal：Carbon
Researcher's Information： Norio Tokuda
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