ORIENTATION EFFECTS IN THE RESISTIVITY OF Ta FILMS SPUTTERED IN OXYGEN

Tantalum films deposited by sputtering in an O–Ar mixture consist of the tetragonal β phase. As the flow rate of the mixture into the sputtering system increases, the preferred-growth orientation changes from (200) to (202) and the resistivity ρ increases from 265 to 1100μΩ-cm. The value of Δρ/ΔT decreases monotonically with increasing (202) orientation, suggesting that the electrical properties are due to the β-Ta phase rather than to intergrain tunneling.