By BioNanoNet
New questions for thermal management arise due to progressive device miniaturization and an increasing level of device integration (1). In particular, for the development of novel materials, significant advances in the understanding of the energy transport at the nanometre scale are necessary (2). Scanning Thermal Microscopy (SThM) enables local thermal characterisation with a high spatial resolution in the nanometre range, overcoming conventional thermal characterisation techniques, which are often subjected to the optical diffraction limit. SThM follows the same principle as standard scanning probe microscopy, but uses probes with an incorporated electrically resistive element. By tracking changes in resistivity of the probe, thermal properties of the scanned sample surface are monitored. SThM at our facilities can be operated inside a Scanning Electron Microscope (SEM). This enables to visualize the SThM probe together with the sample surface. Thus, the SThM-probe can be placed with nanometre precision on surface features of interest. Moreover, the SEM electron-beam can be used as a nanometre sized heat-source, for advanced thermal characterisation at material interfaces or across grain boundaries. The SThM-SEM combination further uses a sophisticated measurement technique based on frequency modulation (3), which enables not only qualitative, but also quantitative measurements of local thermal conductivities. Examples for application fields of the SThM-SEM combination are characterisation and optimisation of nanostructured materials, like multilayer-systems and composite materials, or of integrated nanowires, which are promising for next generation gas sensor devices (4).
