Thermal diffusivity of diamond/Si composite films measured by an ac calorimetric method

Thermal diffusivity of diamond Si composite I]lms was measurcd in the direction parallel to the phme of the film by an ac calorimetric method. The effect of twodimensional heal condt,ction on the measured results appears to be due to the diflcrence in tile thermal diflusivities of tile layers. The thermal diffusivity measured by the thermocottple attached on the diamond side was higher than that on the silicon side. This might be due to the two-dimensional effects. As a result, the estimated thermal diflʹusivity of the diamond layer from the result of composite lilm detected on the diamond side is higher than that detected on the Si side. This gives rise to an error in the estimated thermal diffusivity of the diamond layer. A criterion Ibr the deviation of the estimated thermal diffusivity is proposed.