Optimized Designing to Improve Electrical Characteristics of 4H-SiC Wide Trench Junction Barrier Schottky Diode

Abstract

In this paper, we analyzed a wide trench junction barrier Schottky (WTJBS) diode that improves the current density without increasing the reverse leakage current by using a shallow and wide trench etching process to overcome the trade-off limit. The wide trench etching of the WTJBS produces a deeper junction depth, similar to the trench junction barrier Schottky (TJBS) diode, to offer a similar reverse leakage current. On the other hand, the WTJBS has a higher current density than the TJBS, as it has the extra area of the Schottky junction from the exposed trench sidewall in a limited cell pitch space. Meanwhile, the WTJBS has the design limitation that the trench depth, p(+) junction space, and p(+) junction depth have to be designed optimally for a lower reverse leakage current. We analyzed this structure using device simulation and modeling. By comparing the results of the simulations under the same conditions, we found that the WTJBS has an enhanced current density and a small leakage current compared with the TJBS and the junction barrier Schottky (JBS) diode. This study shows that, using a suitable trench etching process, we can improve the current density of SiC SBDs with low leakage currents. The proposed structure and the designing margin of the WTJBS can propose designing possibilities customized to SiC processes with technological limitations to be incorporated into the next generation of high-voltage 4H-SiC SBDs, along with the addition of simple processes.