Annealing effect on the electrical properties and microstructure of embedded Ni–Cr thin film resistor

Ni–Cr (80/20 at.%) alloy was deposited on the copper foil substrate as embedded thin film resistor (ETFR) materials by DC magnetron sputtering method. Electrical properties and microstructure of Ni–Cr ETFR under different annealing conditions were investigated. Results indicated that the ETFR exhibited the smallest temperature coefficient of resistance (TCR) after annealing at 250 °C for 540 s in N2. The structure, stress, composition and surface morphology of ETFR materials were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS) and atomic force microscopy (AFM). The rarely reported hexagonal Ni (0 1 1), (0 0 2) and (1 0 3) in Ni–Cr thin film were found in Ni–Cr (80/20 at.%) ETFR materials. The chemical states on the surface of the ETFR materials after annealing were mainly Cr2O3. The segregation of chromium during annealing can affect the resistivity and temperature coefficient of resistance (TCR). The different surface morphology of ETFR in annealing will affect the resistivity.

► Annealing effect on the properties of embedded Ni–Cr thin film resistor. ► A good annealing condition was achieved. ► The rarely observed hexagonal Ni (0 1 1), (0 0 2) and (1 0 3) were found. ► The segregation of chromium in thin film can affect the resistivity and TCR. ► The results obtained would be helpful in achieving a good embedded resistor.