Ion beam-assisted deposition of nitrides of the 4th group of transition metals

The nitrides of the reactive transition metals of the 4th group (Ti, Zr, Hf ) exhibit a number of technologically interesting properties such as high m elting points, high hardness, chemical inertness, and decorative appearence . They can be formed by ion beam-assisted deposition at substrates held at room temperature. The nitrides were deposited on silicon by electron beam e vaporation of the respective metal under nitrogen ion bombardment with medi um to high ion energies (10-30 keV). X-Ray photo electron spectrometry show ed that the metals tend to incoporate large amounts of oxygen. This can be reduced by intense ion irradiation. By X-ray diffraction measurements phase formation was determined as a function of the ion-to-atom arrival ratio. T he grains show a preferential (100) crystal orientation. The formation of t his texture depends on the ion-to-atom arrival ratio and on the metal atomi c mass. The films grow in columns which are composed of small crystallites. (C) 2000 Elsevier Science S.A. All rights reserved.