The Effect of The Light Elements Nitrogen, Carbon and Oxygen on The Physical Properties of Sputtered Tantalum Films

Abstract

The structural and electrical properties of reactively sputtered tantalum films are shown to be a strong function of the nitrogen, carbon and oxygen concentration in the films and of sputtering voltage. Transitions from the tetragonal β-Ta structure to a mixture of β-Ta and bcc-Ta, and finally to a single phase bcc-Ta region, followed by nitride, carbide or oxide phases have been observed by X-ray diffraction. In addition, film structure has been correlated for two sputter conditions to Ta-film composition as determined by Auger electron spectroscopy combined with ion sputtering during analysis. It will be shown that once the functional relationships between sputtering voltage, composition and film properties have been established, the monitoring of resistivity, TCR, and spectrophotometry of 60 V anodic films can serve a diagnostic control function in the deposition of the Ta-film component materials.