A sub-200 nanometer wide 3D stacking thin-film temperature sensor

We developed a series of thin-film thermocouples (TFTCs) made from Cr, Au, and Pd long stripes with a width of 90-300 nm and a 10 nm insulating HfO2 layer. The sensors have a three-dimensional sandwich structure, therefore reducing the total width down to 138 nm. Their sensitivity (thermopower) values were measured to be 9.6 + 0.7 mu V K-1 for the Cr/HfO2/Pd sensors and 3.6 +/- 0.1 mu V K(-)1 for the Au/HfO2/Pd sensors. These sensors showed reproducible and reliable measurement performance with a good temperature resolution of 0.04-0.1 K and a small heat capacity of 3.2-3.5 x 10(-14) J per K permicron length, making them promising candidates for applications in electronic devices, microfluidic systems, and single cell or sub-cell detection as built-in sensors.