XPS, AES, and EELS characterization of nitrogen-containing thin films

Pulsed laser deposition (PLD) appears to be a very efficient tool for material synthesis. Interstitial compounds like hydrides, carbides, and nitrides are usually produced by reactive variations of PLD. In this study, a methodical routine based in PLD is used to synthesize nitrogen-containing films by ablating pure-element targets in molecular nitrogen environments. The resulting films are analyzed in situ by X-ray photoelectron (XP), Auger-electron (AE), and electron energy loss (EEL) spectroscopies. Our methodology confirms the existence of remarkable regularities in the spectroscopic characteristics of those films. For example, the N-KVV Auger transition for nitrogen contained in d-metals is split in three main energy bands and several additional subbands. For the main bands, their relative intensities correlate with electronic populations in d-orbitals, while the subbands can be associated to energy losses of the main bands. We propose that the main bands reflect the bonding, non-bonding and anti-bonding interactions between nitrogen and partner element. By means of XPS measurements, core-level energy shifts are detected and they are relative to the amount of nitrogen incorporated in the films. In the EELS section, an association between the loss-structure of pure-elements and nitrides is presented. With few exceptions, the bulk plasmon energy in nitrides is larger than in pure-elements, indicative of an increase in the electronic density of nitrides. The peak structure of the N-KVV transition, the XP binding energies and the loss spectra are presented; this data can be of valuable assistance for the analysis of nitride formation.