Electrical characterisation of AlCuMo thin films prepared by DC magnetron sputtering

AlCuMo films were prepared on Al2O3 substrates at room temperature as a function of Mo concentration by DC magnetron sputtering and were then annealed at various temperatures in air and N2 atmospheres. The effect of annealing temperature on the structural and electrical properties of the films was systematically investigated. Increase in Mo content produced a decrease in temperature co-efficient of resistance (TCR), an increase in resistivity (ρ) and an improvement in long term stability (∆Ω/Ω) of the films. SEM studies revealed that crystallisation and grain growth of the structures took place as annealing temperature increased. TCR varied from negative to positive and further improvements in resistance stability of the films were also achieved through increasing annealing temperature in both air and N2 atmospheres. A temperature region is proposed where ‘near zero’ TCR (±5ppm/oC) and long term stability of better than 0.2% can be realised.