Optimisation of the Fabrication of Sidewall-Implanted Trenches in a 3.3 kV SiC Semi-Superjunction Schottky Barrier Diode
Publication date: 1 Giu 2025
In this paper we demonstrate a fully optimized process flow for silicon carbide semi-Superjunction (semi-SJ) Schottky barrier diodes, achieving high performance with readily available foundry technology. Using $\text{SF}_{6}$ -based etching, we fabricated 7 $\mu\mathrm{m}$ deep trenches with smooth, well-angled sidewalls (80-85°) and optimized implantation of the trench bottom and sidewalls. Scanning capacitance and atomic force microscopy, combined with TCAD simulations, confirmed the successful sidewall doping implantation. The resulting structures are expected to exhibit an RDSON of 6.2 $\mathrm{m}\Omega\cdot \text{cm}^{2}$ and a 4 kV breakdown voltage, outperforming planar diodes. These advancements enable seamless integration of semi-SJ technology into SiC power devices, paving the way for next-generation high-voltage applications.