Thermal dissipation and heating continue to limit the performance of many state-of-the-art electronic and optoelectronic devices, as well as integrated circuits. Here, we present evidence of non-Fourier heat transport at room temperature for submicron heat sources on Si, SiGe, and InGaAs films. Using full-field thermoreflectance imaging, we measure the dynamic temperature of active devices with sub-nanosecond time resolution.   Through image  deconvolution techniques, we achieve far-field resolutions below the diffraction limit, reaching 100–200 nm, enabling unprecedented spatial detail. These image processing methods can also facilitate fast dynamic thermal simulations for 3D integrated circuits.  

Finally, we provide an overview of interface and thin-film thermal characterization, in-plane and through-plane thermal coupling in 2.5D/3D stacks, and highlight some of the latest AI-assisted thermal analysis techniques.