EFFECT OF THE DEPOSITION TEMPERATURE ON THE IRIDIUM FILM MICROSTRUCTURE PRODUCED BY METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION - SAMPLE CHARACTERIZATION USING X-RAY TECHNIQUES

The iridium films were prepared by metal-organic chemical vapour deposition (MOCVD) via the pyrolysis of iridium tris(acetylacetonate) on glass and quartz surfaces at atmospheric pressure with hydrogen as an additive in the deposition temperature range 370-550-degrees-C. The phase composition and the microstructure of the films have been studied by means of the X-ray phase analysis and small-angle X-ray scattering techniques. Only the crystal phase of metal iridium has been found. The films consist of chaotically oriented close-spaced particles of different shapes and sizes. Iridium crystallites and other inhomogeneities of electron density in the films have a mean size in the range 100-400 angstrom. The analysis has made it possible to assume the presence of particles of two shapes in Ir films: ''compact'' (the axial ratio is no lower than 1:3) and ''flattened-out'' (disks, cracks, plates and shells) particles. For all the samples, the mean thicknesses r of ''flattened-out'' particles with spherical shells taken as models of their shapes have been estimated. The value of r increases with increasing substrate temperature from 370 to 470-degrees-C. The maximum volume share of ''flattened-out'' particles is observed in the 420-470-degrees-C deposition temperature range. An increase or a decrease in substrate temperature in MOCVD processes leads to almost complete disappearance of the particles of this shape. The average radii R(g) of gyration and the maximum distances L(max) in particles have been estimated. In addition, the specific surfaces S/V of film material and the functions of volumetric distribution D(v)(R) of compact particles in Ir films have been calculated depending on the deposition temperature.