Simultaneous thickness and thermal conductivity measurements of thinned silicon from 100 nm to 17 <i>μ</i>m
Ethan A. Scott, Christopher Perez, Christopher B. Saltonstall, David P. Adams, V. Carter Hodges, Mehdi Asheghi, Kenneth E. Goodson, Patrick E. Hopkins, Darin Leonhardt, Elbara Ziade
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.