Achievement

IGERT Fellow Elizabeth Ellis has been working to understand the role of phase transformations in the development of a very unusual microstructure in tantalum thin films. This microstructure is unlike anything seen in polycrystalline metal films before, in that it shows continuous orientation gradients and discontinuous grain boundaries. Some films even show a long-range, nonrandom distribution of orientations, which cannot be explained using current models of film growth. Tantalum films are widely used in the electronics industry, especially in the making of tantalum oxide thin film capacitors; however, various technological challenges exist in making these capacitors, and understanding this microstructure will be vital in designing future generations of tantalum oxide thin film capacitors to have appropriate properties and longevity. XRD, EBSD, and SEM cross-section images suggest that the transformation proceeds from the film-substrate interface up through the thickness of the film.