Electronic and mechanical properties of Al (100)/6H–SiC (0001) interfaces: a first-principles study

The electronic and mechanic properties of Al (100)/6H-SiC (0001) interfaces are investigated in detail using the exact first-principles density functional theory calculation. Two types of interfaces, C- and Si-terminated, are considered in this work due to the different atom species at the 6H-SiC (0001) surface. Total energy calculations for these two types of interfaces reveal that the C-terminated Al (100)/6H- SiC (0001) interface has strong interfacial bonds with a large work of adhesion rather than the Si-terminated one. A detailed analysis of the bonding mechanism, hybridization of the surface states and charge transfer reveals the strong covalent character of the bonding for the Al (100)/6H-SiC (0001) reaction interface. By comparing the work of separation of different cleavage surfaces, we find that, for the Al (100)/6H-SiC (0001) interfaces, the fracture tends to occur at the Al-Al bonds, rather than at the C (Si)-Al bonds. Although the C-Al bond ( E a d = 4.85 J / m 2 ) is stronger than the Si-Al bond ( E a d = 3.35 J / m 2 ), it is easier to fracture at the Al-Al bond near the C-terminated Al (100)/6H-SiC (0001) interface because of its lower work of separation ( W s e p = 1.90 J / m 2 ) and tension strength ( γ = 11.55 G P a ).