Comparison of Short-Circuit Safe Operating Areas Between the Conventional Field-Stop IGBT and the Superjunction Field-Stop IGBT

This paper studies the short-circuit safe operating area (SCSOA) of the conventional field-stop (FS) IGBT and the superjunction (SJ) FS IGBT, based on 1200 V-rated samples, with the help of numerical electrothermal simulations. The results show that the peak electric field influences the distribution of the temperature inside devices and plays a crucial role in determining their SCSOAs. When the doping concentration of the collector,$\text{N}_{\mathrm{ C}}$, is low, the peak electric field exits near the collector. Both types of IGBTs have a long short-circuit time,$\text{T}_{\mathrm{ SC}}$, which can exceed$15~{\mathrm {\mu }}\text{s}$.$\text{T}_{\mathrm{ SC}}$decreases with the increase of$\text{N}_{\mathrm{ C}}$because the peak electric field transfers to near the channel. The introduction of the SJ structure weakens the peak electric field and increases$\text{T}_{\mathrm{ SC}}$. The difference is at least 4$\mu \text{s}$and up to 6.87$\mu \text{s}$, when$\text{N}_{\mathrm{ C}}$ranges from 2.0$\times \,\,10^{17}$cm$^{-3}$to 1.1$\times \,\,10^{18}$cm$^{-3}$. Besides,$\text{T}_{\mathrm{ SC}}$of the SJ IGBT can be increased by using highly-doped pillars.