Optimization of Si3N4 interfacial adhesion with nitride and carbide coatings

Silicon nitride (Si 3 N 4 ) has a wide range of applications. In microelectronic devices, it serves as a dielectric and protective layer and is deposited on a silicon substrate and subsequently covered by another coating for further protection. The stability of this layered structure depends on the adhesion at the Si 3 N 4 /coating interface. In this work we utilized density functional theory to investigate the interfacial stability of Si 3 N 4 with series of 15 nitrides (TiN, AlN, CrN, FeN, BN, NbN, TaN, VN, ZrN, WN, CoN, MoN, ScN, YN, and HfN) and 10 carbides (SiC, TiC, MoC, NbC, TaC, VC, ZrC, ScC, WC, and HfC) considering multiple surfaces and orientations (112 in total). While Si 3 N 4 /TiN is known to form a stable interface, the work of adhesion showed that AlN, ScN, TaN, and SiC provide even stronger interfacial bonding with Si 3 N 4 , making them potential replacements for TiN as the overlaying coating. By analyzing the parameters governing adhesion strength, we identified that the electron density at the interface serves as a predictor of adhesion strength across all 25 coatings. This finding provides a practical descriptor for screening and designing nitride and carbide coatings, enabling more efficient selection of materials for Si 3 N 4 -based microelectronic devices.