Thermal Effusivity Calibration Procedure for Thermal Microscope

Abstract

In this paper, a thermal effusivity calibration procedure is proposed using a numerical calculation and measurement of a phase lag of a thermoreflectance signal based on a periodic modulation thermoreflectance method for a thermal microscope. To improve the accuracy of the estimated thermal effusivity, the profile determination of the heating and probing laser beams and the numerical calculation of phase lags with a two-layer model in a threedimensional heat conduction equation are carried out. Results of the experiments of beam profile determination and numerical calculation showed that the estimated values of thermal effusivities are in good agreement with the standard values of silicon, germanium, and Pyrex ® samples. We are convinced that the use of a thermal microscope with numerical calibration is becoming an accurate and precise thermal property measurement technique for the microscale range.

Evaluation of the thermal effusivity of intermetallic compounds using a modulated thermoreflectance method

“…A temperature response simulation was conducted using the TR method [14][15][16] and Fig. 8 presents the simulation model.…”

“…These techniques measure the entire sample, whereas the thermoreflectance (TR) method is a measurement method in which a laser beam is focused to a few micrometers by an objective lens and the thermal properties of the region under the laser are measured. 2,6,[14][15][16][17][18][19][20][21][22] In this method, the temperature dependence of the reflectance of the target metal is used for measurement. Over the past few decades of research on the TR method, metal thin films have played an essential role as reflectors.…”

“…Generally, the TR method is used for Mo thin films deposited using physical vapor deposition methods such as vacuum deposition and sputtering. 14) In the TR method, a periodically modulated heating laser is irradiated onto a sample surface with a thin metal film deposited on it, as shown in Fig. 1.…”

“…Finally, we attempted to estimate the volumetric heat capacity, which is the product of the density and heat capacity, of the IMCs through numerical calculations using the obtained thermal effusivity and phase lag, and converted the results into thermal conductivity. [14][15][16] 2. Experiments…”