The company Hella Saturnus Slovenija d.o.o. manufactures products for the automotive industry that often incorporate resistive heating elements embedded in polymers. Resistive heaters can also be based on (transparent) conductive thin films.
The most used material in industry for transparent conductive thin films is In2O3–SnO2,
indium tin oxide (ITO).
The aim of this work was to evaluate the optical and electrical properties of ITO thin
films that could potentially replace wire-based heating elements. Using sputtering deposition, we prepared six batches of ITO thin film samples, four among them were transparent. We used three different targets – two metal and one oxide. We deposited the films onto polycarbonate, glass, and silicon substrates. For the transparent batches, the ITO film thickness was measured using profilometry, optical transmittance in the visible spectrum by UV–VIS spectroscopy, and layer resistance using the four-point probe method. Radar performance was evaluated using
the RMS (Radome Measuring System) and QAR (Quality Automotive Radome) methods. The microstructure of the ITO thin films was analysed using scanning
electron microscopy (SEM), while their chemical composition was determined by energy-dispersive spectroscopy (EDS).
From the results obtained by measurements and analyses, we concluded that an increase in ITO film thickness leads to a reduced optical transmittance in the visible spectrum and a lower layer electrical resistance. The chemical composition of ITO thin films also changes with film thickness.
|
