Atomic Layer Deposition of Tantalum Oxide and Tantalum Silicate from Chloride Precursors.

The atomic layer deposition (ALD) of Ta2O5 and TaSiO x from TaCl5, SiCl4, and H2O is reported. Both processes are influenced by the concomitant etching of Ta2O5 and TaSiO x by TaCl5. The optimum deposition temperature is found to be 250 °C for both Ta2O5 and TaSiO x. For lower deposition temperatures, the large Cl contamination leads to poor dielectric properties of the films, whereas higher temperatures lead to poor within-wafer (WiW) thickness non-uniformity due to etching. Si incorporation is limited to Si/(Si + Ta) ∼ 0.65 because of the slow adsorption kinetics of SiCl4 on SiOH-terminated surfaces. Under optimum conditions, amorphous films with good dielectric quality are obtained. [ABSTRACT FROM AUTHOR]