Temperature Measurement Accuracy of Thin-Film Heaters for Quartz Crystal Microbalances

This work explores the dual functionality of thin-film platinum deposits, investigating their potential use as both temperature sensors and micro-heaters. Specifically, it examines the stability at medium-high temperatures of thin platinum films deposited on quartz crystal microbalances (QCMs), designed for thermo-gravimetric analyses. The tested QCMs incorporate embedded resistors fabricated via particle vapour deposition of a Ti-Pt bilayer, enabling their operation as either heaters or temperature sensors. Literature suggests annealing influences the electrical resistance stability in high-temperature environments, but scarce information is available about the stability of such films if subjected to self-heating, as when they are used as heating elements, or about their applicability as simultaneous heaters and temperature sensors. The research activity wants to explore the above-mentioned points by testing multiple QCMs up to about $250^{\circ} \mathrm{C}$, a temperature obtained by self-heating of the deposited thin film. Experimental findings indicate that the stability of the deposited films is granted, and a linear correlation between the heater’s electrical resistance change and QCM temperature is obtained, demonstrating their possible usage as temperature sensors for the intended application. Moreover, thanks to the achieved simplification of the instrument architecture, the obtained result opens the possibility of developing new sensor layouts and measurement techniques for high-temperature thermogravimetric analyses.