I. Tomov

Columnar structures in polycrystalline thin films developed by competitive growth

Abstract The formation mechanism of columnar structures is analysed by the investigation of texture and morphology of oxygen-contaminated aluminium thin films. The responsible mechanism for the structure evolution is the oxygen-induced competitive growth that results in an inhomogeneous structure of small-grained and V-shaped columnar morphology and in the appearance of 〈311〉 and 〈100〉 texture. The increase in the oxygen incorporation induces competitive growth of initially formed randomly oriented crystals due to the anisotropy of the chemical interaction of oxygen with the different crystallographic faces. At high-oxygen contamination level, the growth morphology of films is changing to a lower zone of the structure zone models.

Correlation between texture and average grain size in polycrystalline Ag thin films

Abstract The texture and average grain size are investigated in series of silver thin films deposited at various substrate temperatures and different vacuum conditions, by introducing the ‘structure curve’, which describes their correlation. Its slope gives information on the relative contribution of normal and abnormal grain growth to the structure evolution. In contaminated films normal grain growth is suppressed. The texture sharpness has a maximum both in clean and contaminated films above 200°C. This maximum corresponds to 1 and 0.5 μm average grain size in clean and contaminated films, respectively.

Texture, twinning and secondary extinction of vacuum deposited silver thin films

Abstract In the present work the texture, secondary extinction and twinning of vacuum evaporated Ag films have been studied using standard X-ray diffractometer and texture diffractometer techniques. The films exhibit a sharp multicomponent texture: a main 〈111〉 component accompanied with a twin-related 〈511〉 component and a weak 〈100〉 component. It is shown that the correct evaluation and interpretation of the structural properties requires secondary extinction to be taken into account. The effect of secondary extinction on volume fraction measurements of texture components is evaluated on {111} pole figures. The systematic error due to extinction could be considerably decreased when the {200} pole figures were used for the calculation of volume fractions, where the extinction effect is much smaller compared to that of the former one. The correct evaluation of pole-density values in low-index crystal directions was performed allowing for secondary extinction.

Texture and secondary extinction measurements in Al\Ti stratified films by X-ray diffraction

Abstract In the present work the effects of secondary extinction has been studied using standard X-ray diffractometer and texture diffractometer techniques. For this purpose the texture of Al\Ti stratified films have been measured and evaluated. It is shown that these films have a very sharp single component texture. Therefore the evaluation and the interpretation of the measurement data is only possible when secondary extinction correction is carried out. The effect of secondary extinction is evaluated on the 111 pole figures of the stratified films with different layer pair numbers. The volume fraction of the main texture component is calculated from pole figures and it is shown that the grains of the films are practically completely oriented with 〈111〉 crystallographic direction parallel to the film surface normal. Moreover in the case of pole density measurements the secondary extinction values themselves are simultaneously calculated.

Thickness Measurement of Thin Textured Films by a Novel X-Ray Diffraction Method Accounting for Secondary Extinction

Accounting for secondary extinction (SE) of the intensities measured from a textured film by means of conventional X-ray diffractometer, a new X-ray diffraction method is described for determination of film thickness. Physically, the problem is restricted to using a reflection pair corresponding to the main component of the texture. As model sample a vacuum-deposited silver thin film is used.

Texture and grain structure in polycrystalline silver films deposited by partially ionised beam

The analysis of grain growth mechanisms is carried out by the investigation of the correlation between texture and average grain size in polycrystalline silver films deposited by e-beam evaporation. The results indicate that the ion bombardment can enhance the texture evolution by changing the driving force for abnormal grain growth. This effect is attributed to the enhanced desorption of impurities from the free surface of the films due to ion bombardment.

Ultrasharp textures in Al/Ti layered structures

Abstract The aim of the present work was to reveal the structure characteristics of Al/Ti layered structures. For this purpose, conventional (CTEM), high-resolution transmission electron microscopy (HRTEM) and standard X-ray diffractometer measurements have been applied. The layered Al films exhibit an ultrasharp 〈111〉 texture. The 〈111 〉 pole density of the films increases linearly with increasing number of Al/Ti layer pairs. The Al layers contain grains oriented in the 〈111〉 crystalline direction only. The texture sharpness in the single Al films decreases with increasing thickness of the Ti underlayer.

Accounting for Secondary Extinction in Thickness Measurement of Thin Films by X-Ray Absorption

Allowing for secondary extinction (SE), a method is described for thickness measurement of thin films by x-ray absorption. The method is tested by employing Al foils and electrodeposited Cu films detached by the substrate. The thicknesses determined by the method were in fair agreement with that ones measured by the ordinary absorption method based on using incident beam intensities. Moreover, a dependence of the SE coefficient on the transmission factor of the films was experimentally shown, and thus additional light was thrown on the nature of SE.

Single Reflection Method for Pole-Density Measurements Accounting for Secondary Extinction in Textured Films

A method of pole density measurements is described, which uses the differences in X-ray beam polarisation of two monochromators. The method requires a single reflection at an intermediate diffraction angle. Experimental verification is provided by pole density measurements of Ag films and comparison the results obtained with the proposed method with results from the reflection-pair method [8-10].