The research group, from the University of Tokyo and Mitsubishi Electric, has quantified three electron-scattering mechanisms; which are surface roughness of a silicon-carbide channel surface, charge scattering and atomic vibration scattering.
The impact that charges and atomic vibration have on electron scattering under the SiC interface was revealed to be dominant in Mitsubishi Electric's analyses of fabricated devices. A planar-type SiC metal-oxide-semiconductor field-effect transistor (SiC-MOSFET), in which electrons conduct away from the SiC interface to around several nanometers, was fabricated to confirm the impact of the charges.
Using an earlier planar-type SiC-MOSFET device for comparison, resistance was reduced by two-thirds owing to suppression of electron scattering, which was achieved by making the electrons conduct away from the charges under the SiC interface.
"Going forward, we will continue refining the design and specifications of our SiC MOSFET to further lower the resistance of SiC power devices," says Mitsubishi Electric's Yamakawa. This research achievement was published at the 63rd International Electron Devices Meeting (IEDM) in San Francisco, California, on December 4, 2017.