Abstract
Ta films were deposited by dc diode sputtering in Ar–O2. The crystalline structure of the deposited films was investigated by wide‐film Debye‐Scherrer x‐ray diffraction. Films were β‐Ta at low O2 partial pressures, passing through a crystalline suboxide to the bcc phase with increasing O2 content. The results contradict recent suggestions that β‐Ta is formed to accommodate higher impurity levels.