Mechanical Stress Effects on 4H-Silicon Carbide Power Diodes

This study discusses the effect of stress on 4H-silicon carbide (4H-SiC) power diodes using numerical simulations. Two power diodes were evaluated; namely, a 600 V PiN diode and 1.8 kV junction barrier Schottky (JBS) diode. Stress changes the carrier mobilities in the material of the PiN diode of a bipolar diode; that is, the mobility is enhanced by the piezoresistive effect, which minimizes the on-resistance or leakage current. The simulation results demonstrate that compressive stress can have a positive effect on the device operation, particularly in p^+-substrate power diodes. Regarding the JBS diode, the GPa-order tensile stress positively effects both forward and reverse characteristics. A cantilever structure is suitable for JBS diodes, and press-pack packaging for PiN diodes can enhance the device characteristics.