Test structures for ZT thin-film thermoelectric characterization using laser as heat source

In order to improve characterization of thin film thermoelectric materials, a-SixGe1–x:H thin films were deposited by PECVD adjusting temperature, pressure, gas flux and gas ratio. The resulting material has been electrically and thermoelectrically characterized with the TERM-PRU-MA1 microchip, designed for this purpose. A simple method for thermoelectric characterization using a laser as a heat source is proposed. The microchip structures include Schottky diodes made by the union of the thermoelectric material and a metal. One of the proposed applications for the diodes, is using them as micro thermometers. Operated with a constant forward current, Schottky diodes show a very nearly linear relationship between their temperature and the current across them. The thermoelectric test structures were heated controlling the power and pulse of a green laser, using an optical setup. Thermic conductivity and the Seebeck coefficient obtained by this characterization method are similar to the ones obtained with other conventional but more complex methods.