Abstract:
Silicon carbide (SiC) power switches have the advantages of high-speed and high-power, which leads to more severe high d
V/d
t reliability issues than silicon (Si) devices in pulsed power systems. It has been verified by experiments that high d
V/d
t stress will cause permanent degradation of the breakdown characteristics of 4H-SiC PiN power diodes. Simulation results show that there is a strong electric field concentration at the junction between the terminal area of the device and the main junction under high d
V/d
t stress, which causes the avalanche to occur early, and in turn leads to local temperature rise and permanent damage. The electric field concentration is caused by insufficient depletion of the junction terminal extension (JTE) region under high d
V/d
t stress. This paper proposes high-concentration compensation doping to the JTE region so as to increase the ionization rate of aluminum (Al) atoms, thereby improving the insufficient depletion of JTE under pulse stress. Simulation proves that this method can effectively reduce the electric field concentration at the edge of the main junction under pulse stress. The 6×10
20 cm
–3 phosphorus (P) atom compensation doping improves the device's anti d
V/d
t capability by about 30%, while the static characteristics are not affected. The proposed method could be a viable way to improve the d
V/d
t reliability of JTE terminal SiC power devices.