Formation and structure of ceramic thin films deposited by ion beam sputtering

Abstract

An ion beam sputtering apparatus with multiple-ion sources was especially designed to study the film preparation with respect to their chemical structure. Ceramic thin films of TiN, AlN and carbon were prepared by ion beam sputtering of metallic targets. These films were amorphous even under electron microscopic disfraction up to a temperature as high as 1000°C. The composition of thin films which had been intended to produce aluminum nitride strongly depended on the amount of oxygen present in the vacuum. The coordination number of aluminum in aluminum nitride films changed from four to six, depending on the atmospheric chemical composition and sputtering ion sources. When the titanium target was sputtered in the nitrogen atmosphere by an argon ion beam, both TiN and Ti 2N were deposited. The composition could be controlled by changing the partial pressure of argon and nitrogen. The carbon films produced by sputtering the graphite target was a nonconductor, which was considered to be typical of i-carbon. The X-ray spectrum of the carbon film showed a high energy component comparable to that seen in diamond. When the substrate was heated during deposition, the resistance of the deposited carbon films decreased remarkably. Random arrays of small crystallites were characteristic of the i-carbon. Heating the substrate made the crystallites grow to a certain extent.