We investigated the properties of boron carbon nitride him containing hydrogen (BCNH film) deposited using tris (dimethylamino) boron as the source gas. The dielectric constant (k) of BCNH film decreases with decreasing radio-frequency plasma power used for deposition, and can be as low as 1.8 at 10 W. Thermal desorption spectroscopy analysis shows that the film contains a large amount of hydrogen. Fourier transform infrared spectroscopy shows an absorption band at 2960 cm-1, attributed to the asymmetrical stretching mode of C-H in the methyl group. It is thought that increasing the number of C-H bonds, which have a low polarizability, can achieve a lower k value. (C) 2009 Elsevier B.V. All rights reserved.