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

Abstract

Abstract The atomic layer deposition (ALD) of Ta 2 O 5 and TaSiO x from TaCl 5 , SiCl 4 , and H 2 O is reported. Both processes are influenced by the concomitant etching of Ta 2 O 5 and TaSiO x by TaCl 5 . The optimum deposition temperature is found to be 250 °C for both Ta 2 O 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.