Diffusion of TiN into aluminum films measured by soft x-ray spectroscopy

Abstract

Understanding the atomic bonding properties at the interface between thin films is crucial to a number of key modern technical devices, including integrated circuits, magnetic disk read/write heads, batteries, and solar cells. Semi-conducting materials such as titanium nitride (TiNx) are widely used in the manufacturing of modern electronics, requiring a wealth of information about its electronic structure. We present data from soft x-ray emission and absorption experiments involving a sample consisting of a 40 nm TiN layer on top of an aluminum film 550 nm thick. Soft x-ray emission spectroscopy (XES) and near-edge x-ray absorption fine structure (NEXAFS) spectroscopy are tools that provide a non-destructive, atomic site-specific probe of the interface, where the electronic structure of the material can be mapped out element by element. From these measurements, we show that the Ti and the N diffuse into the Al film to form an equivalent material depth of about 4.5 nm, and the NEXAF structure reveals that...