Abstract
$TaN_x$ film is grown by plasma enhanced atomic layer deposition (PEALD) using t-butylimido tris(dimethylamido) tantalum as a metalorganic source with various reactive gas species, such as $N_2+H_2$ mixed gas, $NH_3$, and $H_2$. Although the pulse sequence and duration are the same, aspects of the film growth rate, microstructure, crystallinity, and electrical resistivity are quite different according to the reactive gas. Crystallized and relatively conductive film with a higher growth rate is acquired using $NH_3$ as a reactive gas while amorphous and resistive film with a lower growth rate is achieved using $N_2+H_2$ mixed gas. To examine the relationship between the chemical properties and resistivity of the film, X-ray photoelectron spectroscopy (XPS) is conducted on the ALD-grown $TaN_x$ film with $N_2+H_2$ mixed gas, $NH_3$, and $H_2$. For a comparison, reactive sputter-grown $TaN_x$ film with $N_2$ is also studied. The results reveal that ALD-grown $TaN_x$ films with $NH_3$ and $H_2$ include a metallic Ta-N bond, which results in the film's higher conductivity. Meanwhile, ALD-grown $TaN_x$ film with a $N_2+H_2$ mixed gas or sputtergrown $TaN_x$ film with $N_2$ gas mainly contains a semiconducting $Ta_3N_5$ bond. Such a different portion of Ta-N and $Ta_3N_5$ bond determins the resistivity of the film. Reaction mechanisms are considered by means of the chemistry of the Ta precursor and reactive gas species.
