Thermal sensor properties of cermet resistor films on silicon substrates

摘要

Ni-ZiO{sub}2 cermet films (～1.0 μm thick), with thermal sensitivity superior to Pt and Ni films, were deposited onto Si substrates using a metallo-organic deposition (MOD) technique. Film structure was developed through controlled, reduced atmosphere sintering at 750 ± 50℃ for ≤ 30 min. Resistivity values (ρ) for the cermet films (55 ± 10 vol.% Ni) were in the range of 2.5 × 10{sup}(-4) - 605 × 10{sup}(-2) Ωcm, with linear temperature coefficient of resistance (TCR), i.e. α of up to 4200 ppm/℃. Figure of merit values, defined as the ρα product in these thermal sensors, were of the order of 3 × 10{sup}(-6) and up to 1.6 × 10{sup}(-4) Ωcm/℃ for films with rare earth additives. This compares with ρα of ～2.6 × 10{sup}(-7) and 4.4 × 10{sup}(-8) Ωcm/℃ for Pt based and Ni films, respectively. With these superior sensor properties, the cermet resistor films offer design advantages in size and sensitivity for thermal and flow sensor applications, including low, power Joule heating, high gas flow response, and high bolometer response to IR radiation.