The University of Tokyo and Mitsubishi Electric Corporation reported having developed what they believe to be an all-new mechanism for improving the reliability of silicon carbide (SiC) power semiconductor devices. The researchers initially reported the achievement at The International Electron Devices Meeting (IEDM2018) in San Francisco, California on December 3 (PST).
The researchers realized the new mechanism as a result of proving that the sulfur beneath the interface of gate oxide and SiC captures some of the electrons in the device’s current path, thereby increasing the threshold voltage without altering the device’s on-resistance.
This method is expected to lead to more reliable power electronics equipment with better tolerance to electromagnetic noise. In the future, Mitsubishi Electric intends to continue refining the design and specifications of its SiC metal-oxide-semiconductor field-effect transistor (SiC MOSFET) to further enhance the reliability of SiC power semiconductor devices.
In their research, Mitsubishi Electric designed and fabricated the SiC power semiconductor devices and the analyzed the sulfur’s electron capture in the current path, and the University of Tokyo measured electron scattering.
Until now, electrical engineers had assumed that compared to conventional phosphorous or nitrogen, sulfur is not a suitable element to supply electrons for current conduction in SiC power semiconductors. However, Mitsubishi Electric and the University of Tokyo looked at the ability of sulfur to capture electrons. According to the researchers this ability makes can help make SiC devices less prone to malfunction due to electromagnetic noise.