In this work, we report the effect of substrate, film thickness and sputter pressure on the phase transformation and electrical resistivity in tantalum (Ta) films. The films were grown on Si(1 0 0) substrates with native oxides in place and glass substrates by varying the film thickness (t) and pressure of the working gas (p(Ar)). X-ray diffraction (XRD) analysis showed that the formation of alpha and beta phases in Ta films strongly depend on the choice of substrate, film thickness t and sputter pressure p(Ar). A stable alpha-phase was observed on Si(1 0 0) substrates for t <= 200 nm. Both alpha and beta phases were found to grow on glass substrates at all thicknesses except t=100 nm. All the films grown on Si(1 0 0) substrates for p(Ar)<= 6.5 mTorr had alpha-phase with strong (1 1 0) texture normal to the film plane. The glass substrates promoted the formation of beta-phase in all p(Ar) except p(Ar)=5.5 mTorr. The resistivity rho was observed to decrease with t, whereas rho was increased with p(Ar) on Si(1 0 0) substrates. In all films, the measured resistivity rho was greater than the bulk resistivity. The resistivity rho was influenced by the effects of surface roughness and grain size. Crown Copyright (C) 2010 Published by Elsevier B. V. All rights reserved.