First-Principles Study of Schottky Barrier Heights on Metal/4H-SiC Polar Interfaces

4H-SiC based devices have garnered significant interest within the realm of high-voltage and high-frequency electronic equipment. Schottky barrier heights (SBHs) play a pivotal role in determining the properties of metal/4H-SiC contacts and holding significance for electrical performance of 4H-SiC devices. Herein, the first-principles method is utilized to investigate the interface properties between various metals (Sc, Mg, Zr, Ag, Al, Ru, Rh, Pd, Ni, Au, Ir, and Pt) and 4H-SiC. The results reveal an approximate linear relationship between SBH and work function of these metals. Fermi-level pinning factors are determined to be 0.27 and 0.32 for the Si-face and C-face interfaces, respectively. The disparity in pinning factors arises from polarization differences between the two interfaces, which stem from uneven net charge distribution on the Si-face and C-face. Meanwhile, the SBH values indicate a strong pinning effect, due to the charge transfer occurring at the metal/4H-SiC interface. Through further analysis of layer density and differential charge density, the interatomic interaction and charge transfer between metal and SiC atoms are analyzed. This work offers fundamental insights into the structural changes in metal/4H-SiC interfaces and provides valuable guidance in the potential prediction and optimization of device performance. The research utilizes density functional theory (DFT) calculations to analyze metal contacts at 4H-SiC interfaces. It compares interface and electronic properties among different metals and 4H-SiC, revealing the origin of the pinning effect. The study discusses chemical trends of the polar surfaces, enhancing understanding of the metal/4H-SiC interface and providing insights for optimizing SiC devices.image (c) 2024 WILEY-VCH GmbH