A 4H-SiC MOSFET-Based ESD Protection With Improved Snapback Characteristics for High-Voltage Applications

A novel electrostatic discharge (ESD) protection device based on an n-type metal-oxide-semiconductor field-effect transistor (NMOSFET) with segmented topology was proposed and investigated, considering the material characteristics of 4H-SiC, which is a wide-bandgap material (3.3 eV). ESD phenomena are important in terms of semiconductor reliability, and the benefits of using 4H-SiC as a material can provide robustness and excellent thermal reliability to ESD protection devices. The proposed device improves the wide range of snapback phenomena caused by the high critical electric field (2.4 MV/cm), in comparison to using Si (0.25 MV/cm); it also improves triggering characteristics and provides a high holding voltage. The proposed device and a traditional silicon-controlled rectifier, a gate-grounded-NMOS, and a gate-body floating NMOS were fabricated using the 4H-SiC process. The electrical characteristics of the experimental devices, determined by a transmission-line-pulsing system, were comparatively analyzed. Additionally, this article presents the analysis of the optimization of electrical characteristics according to the critical design variables of the proposed device, stacking for high-voltage applications, and reliability test results for high temperatures (300-500 K).