Search

In this article, a novel SiC superjunction MOSFET with Schottky diode containing N- and P-type barrier is proposed to improving short-circuit and reverse recovery ruggedness, investigated by TCAD simulations. The adoption of superjunction and p-shields structure can reduce saturation current, and thus, improve short-circuit capability. A fine gate oxide providing long-term reliability of the device is obtained. Also, N-type Schottky diode for electrons is used to dampen bipolar conduction of the parasitic body diode, while P-type Schottky diode for holes is introduced to constrain the hole inflow and extraction attributed to the transient variation of the superjunction. As a result, compared with an SBD-wall-integrated trench MOSFET (SWITCH-MOS), a low on-resistance and high breakdown voltage of the proposed structure are gained. More importantly, the proposed device exhibits stronger temperature-dependent immunity. As expected, simulation results indicate that the proposed device under 10 nH stray inductance shows a 30%–50 % reduction in the peak reverse recovery current and a 50%–70 % decrease in the current rising slope of reverse recovery, compared to only a single superjunction, when the metal workfunction varies from 5.1 to 5.6 eV. Moreover, the short-circuit withstanding time of the proposed structure increases roughly 2 times longer than that of SWITCH-MOS. • Dual-type Schottky diodes. • Improving short-circuit capability. • Good reverse recovery robustness. • A good tradeoff between breakdown voltage and specific on-resistance. [ABSTRACT FROM AUTHOR]

The investigation of humidity related failure mechanism (HRFM) is of high importance for reliable operation of IGBTs. Mostly, the investigation of the HRFM is implemented under static voltage conditions. This, however, may be inapplicable because there is an obvious difference between the test condition and the practical condition. To address this, in this paper, the HRFM with the condition of dynamic avalanche is thoroughly investigated. The promoting effects of humidity on the electric field and current density during dynamic avalanche progress are qualitatively analyzed. Then, the temperature and current density distributions of the IGBT module under humidity conditions and normal conditions are compared through simulations. According to the performance comparison, it is revealed that, the humidity makes an obvious contribution to the mutual promotion effect of electric field and current density. Consequently, the operation of IGBT is susceptible to exceed the safe operating area during dynamic avalanche process. Finally, experimental tests are carried out to verify the theoretical analysis. • The humidity related failure mechanism with the condition of dynamic avalanche is investigated. • The technology computer aided design and experimental tests are carried out. • The promoting effects of humidity on the electric field and current density during dynamic avalanche progress are revealed. • The operation of IGBT is susceptible to exceed the safe operating area during dynamic avalanche. [ABSTRACT FROM AUTHOR]