Microstructure of hydrogenated silicon carbide thin films prepared by chemical vapour deposition techniques

We present the results of investigations on a variety of stoichiometric μc-SiC:H films deposited by Hot-Wire- and Plasma-Enhanced Chemical Vapour Deposition using monomethylsilane diluted in hydrogen as precursor gas. Infrared spectroscopy, grazing incidence X-ray diffraction, and Transmission Electron Microscopy were applied and compared to separate the contributions from the different structure phases of the material. It is shown that an evaluation of the crystalline volume fraction from the infrared absorption lineshape of the Si–C stretching mode is not possible, although stated in the literature. A correlation of this lineshape with the material strain is proposed. Moreover, a variation in strain, grain size, and structural defects is found depending on the deposition conditions, but a mixture of an amorphous and a crystalline phase could not unambiguously be identified.

► The microstructure of silicon carbide films deposited by CVD methods is investigated. ► IR absorption could not be linked to a crystalline volume fraction. ► IR absorption lineshape of the Si–C mode was linked to macroscopic strain. ► A variation in grain size and strain was found. ► A mixture of amorphous and microcrystalline material was not observed.