Three-sensor 3ω-2ω method for the simultaneous measurement of thermal conductivity and thermal boundary resistance in film-on-substrate heterostructures

Solid heterostructures composed of substrates and epitaxial films are extensively used in advanced technologies, their thermophysical properties fundamentally determine the performance, efficiency, reliability, lifetime corresponding devices. However, an experimental method that is truly appropriate for property measurement solid still lacking. To this end, a three-sensor 3{\omega}-2{\omega} proposed, which can simultaneously measure thermal conductivities film substrate, along with film-substrate boundary resistance (TBR) single heterostructure without any reference samples, showing broad applicability miscellaneous thickness ranging from 100 nm to 10 {\mu}m. In method, three parallel metal sensors unequal width spacing fabricated on sample surface, two outer as heaters, middle sensor detector. The respective 3{\omega} signals heaters 2{\omega} signal detector measured, then fitted within 3D finite element simulations. verify typical wide bandgap semiconductor heterojunctions, i.e., GaN SiC (#SiC) Si (#Si) ~2.3 {\mu}m epilayers, measured. conductivity film, substrates, GaN/substrate TBRs derived, exhibiting good agreement reported values literature. proposed will provide comprehensive solution measurements various heterostructures.