Thermal imaging using the atomic force microscope

We have developed a new and simple technique for thermal imaging with submicrometer spatial resolution using the atomic force microscope. The method is particularly unique for simultaneously obtaining thermal and topographical images of biased electronic devices and interconnects where there could be different materials and potential variations on a scan surface. Application to a biased metal-semiconductor field-effect transistor showed the heating under the gate and a hot spot between the gate and drain where the electric field is known to be the highest. Thermal images of a biased polycrystalline Al-Cu via structure showed the grain boundaries to be hotter than within the grain. With the development of electronic devices and structures in the submicrometer range, this technique can become very useful as a tool for thermal characterization and property measurement.