Compositon of Tantalum Nitride Thin Films Grown by Low-Energy Nitrogen Implantation: A Factor Analysis Study of the Ta 4f XPS Core Level

TL;DR

This study investigates how low-energy nitrogen implantation affects the composition of tantalum nitride thin films, using advanced XPS analysis and factor analysis techniques to identify phase formations without prior assumptions.

Contribution

It introduces a novel application of principal component analysis and iterative target transformation factor analysis to characterize phase composition in tantalum nitride films.

Findings

Film composition depends on ion dose and energy.

Multiple Ta-N phases are identified, including metallic tantalum and various nitrides.

FA techniques effectively determine phase concentrations without assumptions.

Abstract

Tantalum nitride thin films have been grown by in situ nitrogen implantation of metallic tantalum at room temperature over the energy range of 0.5-5keV. X-ray photoelectron spectroscopy (XPS) and Factor Analysis (FA) have been used to characterise the chemical composition of the films. The number of the different Ta-N phases formed during nitrogen implantation, as well as their spectral shape and concentrations, have been obtained using principal component analysis (PCA) and iterative target transformation factor analysis (ITTFA), without any prior assumptions. According to FA results, the composition of the tantalum nitride films depends on both the ion dose and ion energy, and is mainly formed by a mixture of metallic tantalum, beta-TaN0.05, gamma-Ta2N and cubic/hexagonal TaN phases.