Study on nano-scale thermophysical properties measurement method with Scanning Thermal Microscope

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This research aims to develop the local thermal conductivity measurement method with nano-scale spatial resolution on the scanning thermal microscope. With fabricating the multi-functional micro cantilever probe, its performance has been experimentally examined. The cantilever has 2 micron thick and 600 micron long body of SiO2, and five thermal devices on it. There is electrode of contact thermocouple at the end of the probe for detecting the contact temperature, Pt thin film heater for calibrating heat flow sensor next, thermopile sensor for detecting heat flow along the cantilever, thin film thermocouple for measuring cantilever body temperature and another heater for controlling the body temperature near Si base plate. For the local thermal conductivity measurement with high-accuracy, it is required to measure the contact thermal conductance and the contact temperature simultaneously with high accuracy. The cantilever probe developed in the research enable to calibrate the thermopi … More le heat flow sensor with known heating of the Pt heater, and to identifying thermoelectricmotive force of the thin film thermocouple by using temperature dependency of the heaters. Improvement in accuracy was conducted by eliminating the common ambiguity of the micro-fabricated sensors and introducing the self-calibration functions. It can lead the improvement in thermal conductivity measurement.Following results were obtained by attaching the cantilever probe on the SThM based on the AFM and operating under vacuum condition of below 10^<-4> Pa. The active thermometry, where thermal feedback compensates temperature difference between the cantilever and sample, can be available with higher sensitivity than a previous thermometry probe. Thermal conductance imaging with high spatial resolution can be also available by constantly heating the Pt heater near the tip and monitoring the heat flow from the probe to the sample with the thermopile sensor. Furthermore, the contact temperature is measured with the contact thermocouple at the tip by contacting the probe with the sample coated with gold thin film. It shows that the simultaneous measurement of the thermal conductance and the contact temperature is possible and allows the quantitative local thermal conductivity measurement with the SThM. Less