New Diamond Device Developed with the Use of Ferroelectrics

Abstract:
A new diamond-based Field Effect Transistor, FET, with Ferroelectric gate insulator has been successfully fabricated by the use of organic ferroelectrics VDF-TrFE (copolymer of vinylidene fluoride/trifluoroethylene). VDF-TrFE can be synthesized by the spin-coat method available at a low temperature such as less than 120°C, so it is possible to fabricate devices with damage-free diamond surface. Furthermore, the research team has demonstrated that device operation of this new diamond-based FET is possible even without driving voltage.


The team led by researchers of Kanazawa University together with the researchers of Tokyo University of Science has successfully developed a new diamond-based Field Effect Transistor, FET, with Ferroelectric gate insulator.

Diamond is anticipated to be the ultimate material for power devices because of its superb characteristics. Especially, FET utilizing diamond surface is of high expectation for power devices of next generation. On the other hand, because the diamond surface can be damaged by heat or plasma, ordinary methods for FET fabrication are not suitable, causing destruction of the diamond surface structure. 

The research team, by the use of organic ferroelectrics VDF-TrFE (copolymer of vinylidene fluoride/trifluoroethylene), succeeded in fabricating diamond-based FET for the first time in the world. VDF-TrFE can be synthesized by the spin-coat method already available at a low temperature such as less than 120°C, so it is possible to fabricate devices with damage-free diamond surface. Furthermore, the research team has demonstrated that device operation of this new diamond-based FET is possible even without driving voltage.

By further developing this technology, it is expected not only to fabricate simple diamond devices but to realize diamond-based power devices with very low power loss thanks to excellent characteristics of ferroelectrics.

In the automobile industry where electronics is used more and more, there is a demand that power usage for starting movement of hybrid vehicles, for example, should be effectively or more smartly regulated. The current research outcome based on superb characteristics of diamond is of high expectation to be applied for sophisticated power devices for automobiles.

The research article was published online on Applied Physics Letters on June 13, 2016, a high impact journal in the field of applied physics.

 

figure1

Figure. (a) Cross-sectional schematic diagram and (b) Laser microscopy image of H-terminated diamond surface-channel metal-ferroelectric-semiconductor (MFS)-type FET with circular structure fabricated in this study.

Article
Title: H-terminated diamond field effect transistor with ferroelectric gate insulator
Journal: Applied Physics Letters, 108, 242101 (2016)
Authors: Ryota KARAYA1, Hiroki FURUICHI1, Takashi NAKAJIMA2, Norio TOKUDA1, Takeshi KAWAE1
1Kanazawa University, 2Tokyo University of Science
DOI: 10.1063/1.4953777

Funder
Sakigake Project of Kanazawa University,Matching Plannner Program of the Japan Science and Technology Agency(JST)