On Local Thermal Conductivity Measurement by the SThM

Local thermal conductivity measurement method on the Scanning Thermal Microscope (SThM) has been studied experimentally. Since quantitative measurement of the conductivity requires thermal conductance and another information related to contact area, our new method uses heat flow and contact temperature between a heated cantilever and a sample. The micro thermal cantilever including heater, thermocouple, thermopile and electrode for contact thermocouple was developed. The sample was coated with gold thin film as another electrode for the contact thermocouple. The experiment in the force curve mode operation shows that the heat flow increases and the contact temperature decreases as a contact load increases, and vice versa. Although measured ratio of the conductivity between gold and glass samples were much smaller than the theoretical value, the new method detects difference in the local thermal conductivity.