Modeling interface structures of cubic boron nitride films deposited heteroepitaxially and via a hexagonal boron nitride interlayer on silicon (001) surfaces

Two interface structural models for cubic boron nitride films deposited heteroepitaxially directly and via a hexagonal boron nitride interlayer on the Si(001) surface are proposed according to the characteristics of boron and nitrogen species studied by semiempirical MNDO and PM3. Molecular mechanics optimizations have been performed on a series of cluster structures to support such models. The first interface model shows that the heteroepitaxial growth of cubic boron nitride film directly on the silicon surface is structurally feasible due to 3:2 lattice matches in both (110) and (1 (1) over bar 0) directions. The second interface model shows an alternative way to achieve the cubic boron nitride film via a hexagonal boron nitride interlayer, which completes the two 3:2 lattice matches between the silicon and hexagonal boron nitride and between the hexagonal and the cubic boron nitride, separately. The second model is in agreement with a recent growth of well-oriented hexagonal boron nitride film directly on a Si(001) substrate obtained by us and the widely reported growth of cubic boron nitride him via a hexagonal interlayer. (C) 1997 Elsevier Science S.A.