3.24 – Cubic Boron Nitride Films: Properties and Applications

Cubic boron nitride (cBN) is structurally analogous to diamond, with similar or even superior properties for certain applications. Studies on the low-pressure synthesis of cBN films started around 1980. So far a variety of ion-assisted physical vapor deposition and chemical vapor deposition methods to deposit cBN films on various substrates have been developed. This chapter discusses the major issues hindering cBN films for practical applications, and reviews recent progress in the synthesis and characterization of cBN films, in particular, to increase film thickness, improving crystallinity, reducing residual stress, and enhancing adhesion to the substrates. The merits and demerits of different deposition techniques are discussed. Common features and differences in the structures and properties of cBN films deposited by different approaches are described. This chapter also summarizes up-to-date studies on the mechanical, electronic, optoelectronic, and optical properties of cBN films, and presents example applications of cBN films in cutting tools, deep-ultraviolet detectors, and chemical and biological sensors.