Effects of deposition parameters on tantalum films deposited by direct current magnetron sputtering

The structure, composition, and temperature coefficient of resistance of tantalum films were studied as a function of deposition parameters and substrate temperature. As the sputtering power increases from 25to100W, tantalum films deposited at 300°C consisting of the β phase, the preferred-growth orientation changes from (200) to (202) and the temperature coefficient of resistance reduces from −289.79to−116.65ppm∕°C. The decrease in oxygen and other impurity content in the films was observed when the deposition power was increased. The O∕Ta ratio decrease and grain size reduction, which were related to a change in electrical resistivity, were also observed as substrate temperature was varied from 300to500°C. These results indicated that the electrical properties were related to the oxygen and other impurity content and grain size in the films rather than to growth orientation. At 650°C, the metastable β-Ta phase was partially transformed into the stable α-Ta phase which leads to a sharp decrease in the el...