Electrical properties of micro-heaters using sputtered NiCr thin film

NiCr (80/20 at.%) thin films were deposited on SiO
₂
/Si substrates as a cryonetic heater by DC magnetron sputtering technique. After a series of annealing treatments under various conditions, the electrical properties and microstructure of the films were investigated. The crystallinity and composition of the films were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The films are changed from crystalline to amorphous phase after annealing at 250°C in nitrogen ambient and the annealing conditions have a significant effect on the resistivity and temperature coefficient of resistance (TCR) of the films. TCR of the samples annealed at 250°C for 9 minutes in N
₂
shows 9.23 ppm/K at 20K which is finally confirmed as the optimal result.