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Purpose – The purpose of this work was fabrication of a small energy harvester. Design/methodology/approach – The multilayer thermoelectric power generator based on thick-film and low temperature co-fired ceramic (LTCC) technology was fabricated. Precise paths printing method was used to fabricate Ag/Ni and Ag/PdAg thermocouples on a number of unfired LTCC tapes. The tapes were put together to form a multilayer stack. The via holes were used to make the electrical connections between adjacent layers. Finally, the multilayer stack was fired in the appropriate thermal profile. Findings – It consists of 450 thermocouples and generates output voltage of about 0.45 V and output electrical power of about 0.13 mW when a temperature difference along the structure is 135°C. In the paper, individual stages of energy harvester fabrication process as well as its output parameters are presented. Originality/value – Miniaturized thermoelectric energy harvester based on thick-film and LTCC technology was fabricated. As materials, metal-based pastes were used. This is the first paper where multilayer thermoelectric harvester, fabricated with the aid of LTCC technology, was described. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to investigate the possible application of thick-film, metal-based thermocouples to microsystems power supply. The subject of matter was development of the procedure of thick-film thermopile miniaturisation. Design/methodology/approach – The aptitude of four photoimageable inks (based on silver or silver-palladium) to fabrication of miniaturised thermocouples' arms was investigated. The object of interest was their compatibility with different kinds of low temperature cofired ceramic (LTCC) substrates, maximum resolution, shrinkage and electrical resistivity. Usage of the laser shaping technique to fabrication of narrow thermocouples' arms was also subject of matter. After tests and processes optimization both techniques were combined to fabricate the thick-film Ag/Ni microthermopile. Findings – Most of investigated inks were compatible with all tested LTCC tapes – fired as well as unfired (green tapes). Photoimageable inks technique can be successfully used for thermocouples' arms miniaturization. 40 μm/40 μm line/spaces resolution can be easily achieved. Combining this technique with laser shaping enabled microthermopile fabrication. It consisted of 42 Ag (photoimageable)/Ni (laser shaped) thermocouples. Arms width was 40 μm and 225 μm (Ag- and Ni-arm, respectively), spaces between them – 65 μm. Overall, width of single thermocouple was smaller than 0.4 mm. Practical implications – Fabrication of microthermopile consisting of several hundreds of thick-film thermocouples will be possible if described procedure is applied. Such microgenerator will generate output power sufficient to supply some microsystems or microelectronic circuits. Originality/value – The properties of four photoimageable inks were investigated as well as their compatibility with five different LTCC substrates (fired and unfired). Procedure of thick-film microthermopile fabrication using photoimageable inks technique combined with laser shaping was proposed for the first time. [ABSTRACT FROM AUTHOR]

This work presents the fabrication of thermopiles with high output voltage. A series of mixed thick/thin-film thermopiles were performed -- one of the arms of the thermocouples was screen-printed (PdAg- or Ag-based thick-film layers), the second was made of magnetron sputtered semiconductor (compositions based on Ge). The output parameters (thermoelectric force ET [V], internal resistance Ri [Ω], output electrical power Pout [W]) of the structures were characterized using a self-made automatic measurement system. The best parameters were achieved for TSG/PdAg (TSG -- Ge doped by Sb and Ta) and WSG/Ag (WSG -- Ge doped by Sb and W) structures. Generated output voltage per single thermocouple was about 20 mV and output electrical power -- 0.55 µW, when temperature difference between hot and cold end was 100 K. Also, the influence of activation process on output parameters was investigated (structures were put into high temperature to initialize recrystallization and grain growth process). The possibilities of using of such structures as thermoelectric microgenerators or sensors were considered. TSG/PdAg-based structures were used to prepare laser power sensor. The level of generated thermoelectric force ET was proportional to the power of the laser beam under investigation. Tests of prototype structures showed that thermoelectric sensors have sufficient resolution and ensure very good repeatability of measurements. [ABSTRACT FROM AUTHOR]