The Si_3N_4/TiN Interface: An Introduction to a Series of Ultrathin Films Grown and Analyzed In situ using X-ray Photoelectron Spectroscopy

摘要

Superhard nanostructured materials, such as nanocomposites and nanolaminates, are subjects of intense interest in materials research. The bulk properties of these materials are often defined by the physical and electronic structure of internal interfaces, which are not well understood. The nanocomposites consist of crystallites (≤ 10 nm) of transition metal nitrides, carbides or borides encapsulated by a few monolayers (ML) of a covalent tissue phase (e.g., Si_3N_4, BN, CN_x, or C). Due to the small dimensions of these nanostructures, nucleation and propagation of dislocations is impeded, while the high cohesive strength of the intergra-nular tissue layer inhibits grain-boundary sliding (Ref. 1). The nature of the bonding between the crystallite and tissue phases is an important determinant factor defining the macroscopic properties of these materials. An example of a superhard nanocomposite which has served as a model system is TiN/Si_3N_4.