Netsu Sokutei, 39 (W39), p. 14, (2012)


Nanocalorimeter for DTA and Mass Measurement in High Temperature Range

The introduction of the MEMS technology into thermal sensing enables thermal analysis of minute samples. In our previous study on the cantilever type nanocalorimeter, fast DTA and mass measurement using mechanical resonance for micro- to nano-gram level samples were demonstrated. The use of the nanocalorimeter, however, was empirically limited below 400 oC. In this study, a heat-resistant MEMS calorimeter has been developed to extend the MEMS-based thermal analysis to the high temperature range. The new calorimeter is equipped with platinum thin film devices such as a resistance temperature detector (RTD), a heater and a strain gauge on a SiO2 micro cantilever body. The characteristics of the calorimeter, performance of the DTA and the mass measurement were experimentally studied. It was shown that the annealing of the calorimeter improves the reproducibility of the devices with diminishing electrical resistance change during thermal analysis in high temperature range. In a high temperature DTA test with a micro-gram level aluminum sample, endothermic and exothermic peaks corresponding to melting and solidification were clearly observed. It was demonstrated that the heat-resistant MEMS calorimeter extended the analytical temperature range to up to 800 oC. Moreover a resonance system applicable to high temperature use was developed by introducing the strain gauge into the calorimeter. The resonance mass measurement system demonstrated a performance of nano-gram level mass measurement.