Tunable TCR and Thermoelectric Performance of CoCrFeNiTi High-Entropy Alloy Thin Films Fabricated by Magnetron Sputtering

CoCrFeNiTi high-entropy alloy (HEA) thin films were prepared on Si/SiO 2 substrate by DC magnetron sputtering from one target of Co 0.22 Cr 0.23 Fe 0.29 Ni 0.2 Ti 0.06 composition. The influence of sputtering time and power on the morphology, structure, chemical composition, resistivity, and temperature coefficient of resistance (TCR) has been studied. The thin films of the CoCrFeNiTi alloy exhibit a wide range of properties that can be tailored by adjusting the deposition parameters. The films demonstrate tunable TCR. The best TCR of 2.7±0.8 ppm/°C has been achieved. In addition, a head-to-head comparison with state-of-the-art thin-film resistor materials (NiCr, TaN and HEA analogues) is presented for the first time. The study of the thermoelectric properties of the obtained films has shown the highest PF value of ∼ 0.015 mW/(m·°C 2 ) and the linear behavior of an increase in PF in the range from –196 to 200°C. • Structure and properties of CoCrFeNiTi films rely on sputter deposition parameters • Amorphous or nanocrystalline structure forms depending on deposition time and power • Electric resistivity and thermoelectric characteristics of the films were studied • Temperature coefficient of resistance 2.7±0.8 ppm/ºC from –3 to 67°C obtained • Power factor achieved 0.015 mW·m -1 ·ºC -2 after deposition in the optimal regime