Thermal conductivity measurements of high and low thermal conductivity films using a scanning hot probe method in the 3ω mode and novel calibration strategies

Abstract

This work discusses measurement of thermal conductivity (k) of films using a scanning hot probe method in the 3ω mode and investigates the calibration of thermal contact parameters, specifically the thermal contact resistance (R^th_C) and thermal exchange radius (b) using reference samples with different thermal conductivities. R^th_C and b were found to have constant values (with b = 2.8 ± 0.3 μm and R^th_c = 44 927 ± 7820 K W⁻¹) for samples with thermal conductivity values ranging from 0.36 W K⁻¹ m⁻¹ to 1.1 W K⁻¹ m⁻¹. An independent strategy for the calibration of contact parameters was developed and validated for samples in this range of thermal conductivity, using a reference sample with a previously measured Seebeck coefficient and thermal conductivity. The results were found to agree with the calibration performed using multiple samples of known thermal conductivity between 0.36 and 1.1 W K⁻¹ m⁻¹. However, for samples in the range between 16.2 W K⁻¹ m⁻¹ and 53.7 W K⁻¹ m⁻¹, calibration experiments showed the contact parameters to have considerably different values: R^th_c = 40 191 ± 1532 K W⁻¹ and b = 428 ± 24 nm. Finally, this work demonstrates that using these calibration procedures, measurements of both highly conductive and thermally insulating films on substrates can be performed, as the measured values obtained were within 1–20% (for low k) and 5–31% (for high k) of independent measurements and/or literature reports. Thermal conductivity results are presented for a SiGe film on a glass substrate, Te film on a glass substrate, polymer films (doped with Fe nano-particles and undoped) on a glass substrate, and Au film on a Si substrate.