Theoretical calculations on the adhesion, stability, electronic structure and bonding of SiC/W interface

The beta-SiC(111)/alpha-W(110) interfaces were studied by first-principles calculations based on density functional theory (DFT). The ideal work of adhesion (W-ad) and interface energy (gamma(int)) were calculated for six different interfacial structures, taking into account both Si- and C-terminations of beta-SiC(111) surfaces, and three different stacking sequences. The interfacial electronic structures including charge density distribution and difference, and density of states (DOS) were simulated to determine the nature of SiC/W bonding. The results show that the Si-terminated top-site interface is the most stable interface, yielding the highest W-ad and the lowest gamma(int). During the optimization, the Si-terminated top-site interface will transform into the center-site structure, resulting in the interaction among the interfacial W and Si atoms, and subinterfacial C atoms. In addition, the calculated interface energies show that an interdiffusion layer will form on the SiC/W interface. The experimental results also have verified the existence of an interdiffusion layer on the SiC/W interface in a CVD-SiC fiber. (C) 2014 Elsevier B.V. All rights reserved.