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Update(MM/DD/YYYY):07/08/2019

Development of a 1200-V-class SiC Transistor with a Built-in Schottky Barrier Diode (SBD)

– For development of a high-efficiency, high-reliability power module for hybrid electric vehicles (HEVs) and electric vehicles (EVs) –


Researchers: Shinsuke Harada, Leader, SiC Power Device Team, Advanced Power Electronics Research Center


Summary

The researcher has developed a high-reliability transistor with a unique structure in which built-in diodes does not suffer from current degradation, and verified its performance using a mass-production-quality prototype.

Figure
Ordinary transistor structure with a built-in SBD (left) and developed transistor structure


Background

When voltage is applied to a built-in PiN diode that is structurally integrated into a transistor, the current gradually decreases. To address this problem, a transistor structure with a built-in SBD has been developed for a 3300-V-class transistor. However, the method cannot be applied to a 1200-V-class transistor. There was a need for a transistor with a built-in SBD for this class of withstand voltage.

New findings

The developed transistor has trench type gates and SBD built on a trench sidewall. The cell pitch, i.e., the spacing of the gates, was reduced to 5 µm, less than one third of the conventional pitch. Thus, the voltage applied to the PiN diodes was reduced and a high-reliability transistor that does not suffer from current degradation was developed.

Future plans and potential for application

With commercialization of this technology in mind, the researcher will enhance collaboration with companies and develop a multilayered device structure and an advanced production process. He will also develop peripheral technologies, such as a packaging technology.






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