サーモリフレクタンス法による TiNx 薄膜の熱拡散率の測定

Thermal diffusivity of titanium nitride (TiNx) films normal to the film surface was measured quantitatively using a thermoreflectance technique. TiNx films were deposited on alkali free glass substrate by reactive rf magnetron sputtering using a Ti metal target and mixture gas of Ar and N2. Nitrogen compositions of the film were determined from plasma energy using Bendavid's relation. The ratio of nitrogen to titanium atoms increased from 0.8 to 1.2 when reactive N2 gas composition changed from 4.7% to 100% at the deposition process. For the stoichiometric film, the thermal diffusivity shows peak value, as well as the electrical conductivity. In contrast, when nitrogen composition becomes to over- or under-stoichiometry, both thermal diffusivity and electrical conductivity rapidly decrease, respectively. The relationship between the thermal diffusivity and the electric conductivity suggests that the free electron contribution is dominant to the heat conduction in the TiNx films.