Simultaneous thickness and thermal conductivity measurements of thinned silicon from 100 nm to 17 μm

Abstract

Studies of size effects on thermal conductivity typically necessitate the fabrication of a comprehensive film thickness series. In this Letter, we demonstrate how material fabricated in a wedged geometry can enable similar, yet higher-throughput measurements to accelerate experimental analysis. Frequency domain thermoreflectance (FDTR) is used to simultaneously determine the thermal conductivity and thickness of a wedged silicon film for thicknesses between 100 nm and 17 μm by considering these features as fitting parameters in a thermal model. FDTR-deduced thicknesses are compared to values obtained from cross-sectional scanning electron microscopy, and corresponding thermal conductivity measurements are compared against several thickness-dependent analytical models based upon solutions to the Boltzmann transport equation. Our results demonstrate how the insight gained from a series of thin films can be obtained via fabrication of a single sample.

Lattice Boltzmann method with effective correction of phonon properties for nano/microscale heat transfer

“…Numerical results in one-dimensional and two-dimensional steady state phonon transport Figure 9. Effective cross-plane thermal conductivity of silicon thin films at 300 K and the results of the previous LBM case [24], BTE [52], NEMD [53], experiment data-1 [49], experiment data-2 [50].…”

“…As shown in figures 9 and 10, compared to the previous LBM work [24], experimental data [48][49][50][51] and other methods [52][53][54], the improved LBM scheme generates a better relation between thermal conductivity and the characteristic length. The previous LBM work neglect the decreasing of phonon MFP and relaxation time with increasing Kn.…”

“…The size effect on thermal conductivity of silicon thin films have been investigated in some previous LBM work [24,33]. However, non-negligible difference exists among their results, experimental data and other methods [ [48][49][50][51][52][53][54]. Under the improved LBM scheme, the relation between both in-plane and cross-plane thermal conductivities of silicon films and their characteristic length are investigated.…”