Thermal Boundary Resistance Measurements Using a Transient Thermoreflectance Technique

A transient thermoreflectance technique, using a 200-fs laser pulse, is demonstrated as a nondestructive method for measuring the thermal boundary resistance between a thin metallic film and dielectric substrate. Experimental results are presented for Au deposited on silicon and silicon dioxide substrates taken at room temperature and compared to a thermal model. The relevant thermal properties of the metal film and the substrate are known, leaving the thermal boundary resistance as the only free parameter in the least-squares fitting routine. It is shown that the sensitivity of this technique is related directly to the thermal diffusivity of the substrate. A comparison between the diffuse mismatch model, the phonon radiation limit, and the experimental results indicates that the phonon dispersion relations of the materials can be utilized to give a qualitative prediction of the thermal boundary resistance.