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

摘要

The atomic layer deposition (ALD) of Ta_2O_5 and TaSiO_x from TaCl_5, SiCl_4, andH_2O is reported. Both processes are influenced by the concomitant etching of Ta_2O_5 and TaSiO_x by TaCl_5. The optimum deposition temperature is found to be 250℃ for both Ta_2O_5 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 SiCl_4 on Si-OH-terminated surfaces. Under optimum conditions, amorphous films with good dielectric quality are obtained.