Yttrium nitride thin films grown by reactive laser ablation

Yttrium nitride thin films were grown on silicon substrates by laser ablating an yttrium target in molecular nitrogen environments. The composition and chemical state were determined with Auger electron, X-Ray photoelectron, and energy loss spectroscopies. The reaction between yttrium and nitrogen is very effective using this method. Ellipsometry measurements indicate that the films are metallic. We attribute this behavior to a small oxygen contamination. Each oxygen atom introduces two additional electrons to the unit cell, resulting in a complex semiconductor-ionic-metallic system. These results are corroborated by first principles total energy calculations of clean and oxygen doped YN. (C) 2003 Elsevier Ltd. All rights reserved.