Single-Mask Implantation-Free Technique Based on Aperture Density Modulation for Termination in High-Voltage SiC Thyristors

For the termination in high-voltage SiC thyristor, this article proposes a single-mask implantation-free solution named aperture density modulation technique. Using this technique, the etching profile on the epitaxial layer can be controlled by the aperture layout on the mask. Thus, it can directly form the smoothly tapered junction termination extension with customizable slope profile. The experiments confirm this control ability on profiles with the extension length from 200 to 400 μm. The fabricated devices with the blocking voltage near 8 kV (~80%) demonstrate the feasibility as a termination technique. The numerical simulations present the potential to maintain this breakdown voltage within 120 μm. Therefore, a low-cost solution for high-voltage termination in SiC bipolar devices is expected using this technique.