Barrier Effect of TaSiN Layer for Oxygen Diffusion

Abstract

The barrier effect for oxygen diffusion is studied in TaSiN layers. The TaSiN is deposited by reactive sputtering employing Ta and Si targets. The composition of the layer ranges from to by varying the Ta target power from 100 to 400 watts (W) A resistivity of 210 μΩ cm is obtained for the layer. The surface oxidation and in‐diffusion of oxygen to a depth of 15 nm into the layer are observed by annealing in at 650° C. However, the oxygen diffusion is suppressed in the layer. No out‐diffusion of oxygen occurs from the dielectric layer to the amorphous barrier layer. This result shows that a low Si concentration layer for instance, is a promising barrier layer for oxygen diffusion and is useful for charge storage capacitors for MOS memory devices.