4H-SiC-Based ESD Protection Design With Optimization of Segmented LIGBT for High-Voltage Applications

Abstract

4H-SiC is a wide-bandgap material that exhibits excellent high-temperature conductivity and high operating voltage. These characteristics can provide high electrostatic discharge (ESD) robustness in high voltage applications. However, a considerably wide range of snapback phenomena is triggered for 4H-SiC-based ESD protection devices owing to a high critical electric field. In this study, an ESD protection device based on a lateral insulated-gate bipolar transistor (LIGBT) with a new structure that creates an internal silicon-controlled rectifier (SCR) path is proposed. The proposed ESD protection device minimizes the effective base region of the NPN parasitic bipolar transistor to the gate length based on the internal SCR operation of the LIGBT. It also adjusts the emitter injection efficiency of the PNP parasitic bipolar transistor by introducing a segment topology and inserting an additional implant area. Consequently, the proposed ESD protection device significantly improves the wide range of snapback phenomena occurring in the 4H-SiC materials. A conventional SCR, the LIGBT, and the proposed protection device were fabricated using the 4H-SiC process under the same condition, and their electrical characteristics were comparatively analyzed using a transmission-line pulse system. Moreover, its high-temperature reliability was evaluated at 300–500 K to examine the compatibility with 4H-SiC devices and circuits that require a relatively high-temperature operation.