IEEE Workshop on Wide Bandgap Power Devices and Applications in Asia (WIPDA-ASIA 2021)

In this work, the SiC MPS diodes with hexagonal and circular cell designs are studied and compared regarding the static performance and avalanche capability via experiment and 3D TCAD simulation. The experimental results exhibit that the breakdown voltage of the MPS-B diode (circular cell) is slightly higher than that of the MPS-A diode (hexagonal cell). The Unclamped-Inductive-Switching (UIS) tests are also performed for the two devices, and the MPS-B diode has a better avalanche capability both in terms of avalanche energy/ current capabilities. Simultaneously, the MPS-A diode shows a higher increase rate and higher maximum voltage (V_{d_max}) during the avalanche pulse, meaning a higher junction temperature rise (ΔT_j) and a reduced avalanche capability. The simulation results reveal the electric field of the corners of hexagonal P+ islands is higher than that of the edges of circular P+ islands due to the curvature effect, which leading to a more serious heat crowding and a premature failure. This phenomenon illustrates a smoother design (such as the circular cell design) should be used to replace the corner area and to alleviate the electric field crowding issue, which helps to enhance the avalanche robustness of the SiC device. While a period of indeterminate length (usually short) marked by some action or condition More (Definitions, Synonyms, Translation)

SiC,MPS Diode,Curvature Effect,Avalanche Capability,Cell Design