Properties of Boron Nitride (B _<i>x</i> N _<i>y</i> ) Films Produced by the Spin‐Coating Process of Polyborazine

Abstract

Boron‐rich boron nitride (BN) films have been prepared on Si and SiO 2 /Si substrates by the vacuum pyrolysis of spin‐coated polyborazine films. Physical properties of the prepared films such as film strength, thermal conductivity, and dielectrics were determined. The BN films vacuum‐pyrolyzed at 900°C showed residual N–H bonds with a 0.75 N/B ratio, interdiffusion phenomena, and preferred orientation at the interfacial zone. Hardness and the elastic modulus of the film increased to 1.6 GPa and 50 GPa by nanoindentation loading. It had a thermal conductivity of 134 W/(m·K) at 296.5 K, and a dielectric constant in the range of 5–7, with tan ∂ between 0.01 and 0.47, depending on the film thickness.