Dielectric Properties of Amorphous Carbon Nitride Films

Dielectric properties of amorphous carbon nitride films made by the layer-by-layer method, (LLa-CNx) consisting of a cyclic process with (A) the deposition of an amorphous carbon nitride layer by sputtering and with (B) the etching by atomic hydrogen, have been compared with that of amorphous carbon nitride (a-CNx) films prepared without the hydrogen etching process. It is found that the nitrogen in a-CNx and LLa-CNx could decrease the refractive index n and the dielectric constant e at 1 MHz. The nitrogen could create less dense structure in a-CNx and LLa-CNx compared to diamond-like carbon (DLC). The sp3 bonds between carbon atoms seem to increase by the atomic hydrogen treatment in LLa-CNx. The refractive index of LLa-CNx increases with sp3content. Preliminary experiments adding oxygen in amorphous carbon nitride to create a-CNxOy film are tried and discussed briefly.