Vertical termination filled with adequate dielectric for SiC devices in HVDC applications

Numerous techniques have been used to improve the breakdown voltage (VBR) capability of high voltage devices with the aim of getting closer to the breakdown voltage of a plane parallel junction. In this work, a peripheral protection for a 3 kV SiC bipolar diode is presented. This protection concept is based on a large and deep trench filled by an insulating material. This trench is called Deep Trench Termination (DT²) already validated in Si technology. Our results show that, on the basis of simulations with TCAD Sentaurus, it is possible to protect effectively with this type of trench. The simulation allows to optimize the characteristics of peripheral protection. To take into account the close environment of the semiconductor, the positive and negative fixed charges at the semiconductor - insulating interface have been considered. The work was focused on a 3 kV SiC bipolar diode, but the proposed solutions could be easily scale to any range of voltage.