Search

Thin films of TiN have been deposited by reactive magnetron sputter deposition in varying partial pressures of nitrogen. Reflectivity measurements have been carried out between 1.5 and 3.5 eV and a correlation made between the film properties and optical data. Resistivity measurements carried out at room temperature are shown to exhibit the same trends as those obtained from reflectivity experiments. X-ray absorption fine structure measurements, in both electron-yield and fluorescence-yield modes, have shown the films to be identical and stoichiometric to within ±5 at.%. The use of reflectivity spectra to form the basis of a characterization tool for physical vapour deposited thin films is discussed.

The ionized physical vapor deposition technique uses a built-in rf coil to generate an inductively coupled plasma (ICP) between the target and substrate holder. For deposition of metallic species, a portion of the depositing atoms is ionized upon passing through the ICP. Since the input energy of the ICP is decoupled from the target, this technique also provides controllable ion bombardment during film growth, in terms of bombarding ion flux and ion energy. An ionized physical vapor deposition system has been studied and fully characterized. The ICP was characterized using a single passive probe method, and the plasma parameters, including electron temperature, plasma potential, and plasma ion density, have been measured. The ionization fraction of the depositing metal flux as a function of deposition parameters has been measured using the single passive probe method and a self-developed parallel-plates method. A simplified one-dimensional model was developed and compared favorably with the measured ioniz...

Spatially resolved optical emission spectroscopy has been used to investigate the sputtering and ionization of titanium in a DC planar magnetron using argon as a sputtering gas. Maps of argon and titanium atomic and ionic emission have been obtained. Characteristic emission patterns have been identified and explained by the sputtering of atoms from the magnetron target and their subsequent ionization in the dense plasma at the magnetron target. The inverse Abel transformation was used to reconstruct plasma emission profiles, revealing that the non-uniform erosion profile at the magnetron target leads to a non-uniformity in plasma properties some distance into the discharge. An enhanced metal ionic content has been found in the plasma on the axis of symmetry of the discharge, and this has been explained by an enhanced lateral diffusion of metal ions arising from the change in momentum of sputtered metal during collisional ionization by metastable argon atoms.

Emission spectra in the visible and near ultraviolet have been recorded for the magnetron sputtering of titanium by argon at pressures between 0.5 and 100 Pa. Intense emission lines from both atomic and ionic material were detected, and comparison of line intensities yielded an ionization fraction of over 10% and an electron temperature of the order of 1 eV for the sputtered material. The ionization fraction decreased with increasing magnetron power, and an optimal operating pressure was found for maximum ion content of the sputtered flux. Scaling laws of emission line intensity with magnetron power indicated the incomplete thermalization of sputtered metal with the sputtering plasma, and spatially resolved measurements of ionization profiles were used to investigate the transport and collisional ionization of sputtered material. Penning ionization of sputtered titanium by metastable argon was found to be the dominant ionization process, and the effect of diffusion of metastable argon was noted. Control of ion content in sputtered fluxes is of interest for the deposition of thin films and for metallization of semiconductors.

Tungsten trioxide films were deposited on (100) SrTiO3 and R-plane (10 2) cut sapphire substrates by dc magnetron sputtering, using a tungsten target in an Ar/O2 sputtering gas mixture at substrate temperatures ranging from 500 to 850 °C. Deposited films were characterized by x-ray diffraction using -2 scans and pole figure analysis. X-ray results showed that films deposited on both types of substrate were epitaxial. The equilibrium phase was monoclinic -WO3 , confirmed by Raman spectroscopy. Films on both substrates were (001) oriented. This preferred orientation improved as the deposition temperature was reduced. The in-plane orientation relationship of the films with the substrate was obtained from the pole figures.

A Materials Science overview of the deposition of ceramic superconductors is presented. Whilst in the last four years the major effort has gone into the deposition of YBa2Cu3O7-∂ (YBCO), the bismuth and the thallium compounds will also be considered. The two major techniques of laser ablation and “off axis” sputtering will be discussed as well as evaporation, molecular beam epitaxy (MBE) and metallo-organic chemical vapour deposition (MOCVD). Emphasis will be placed on the in-situ deposition technique for YBCO though some consideration will be given to the “post heat treatment” methods being used for the bismuth and thallium compounds. One of the fundamental issues to be addressed will be the relationship between the deposition conditions and the properties of the films produced. The key issues of nucleation will be discussed, aiming at an understanding of the outstanding problems of preparing smooth uniform films.

Nanoindentation allows the hardness of thin coatings and synthetic multilayer structures to be measured, since indentation depths can be as little as a few 10s of nm. In combination with the cross-sectional transmission electron microscopy (TEM) analysis described here it is possible to observe the deformation structure under an indent, and potentially to understand deformation mechanisms on a nm scale in a wide variety of materials. Synthetic multilayers are a particularly interesting system to investigate. Variations in hardness with the multilayer compositional repeat distance (A) have been reported for several systems. The highest hardnesses, which are in excess of what a simple “rule of mixtures” would predict, occur in nitride multilayers at A ∼5nm. Here we present some preliminary results showing the deformation structure in both a monolithic NbN film and a TiN/NbN multilayer in which both components have the rQck salt structure with lattice parameters 0.424nm (TiN) and 0.439nm (NbN).

Thin films of Ti–Si–N have been deposited by ionized magnetron sputter deposition using separate Ti and Si targets in an Ar/N2 gas mixture. A built-in rf coil generated an inductively coupled plasma close to the substrate. With this setup, the ion flux and energy can be controlled by adjusting the rf power to the coil and the dc substrate bias. Deposition was carried out under various conditions to investigate the effects of different operational parameters on film structure and mechanical properties. Crystallography, grain size, and film texture have been characterized by x-ray diffraction, showing that the addition of Si to TiN films transforms the (111)-oriented structure to a preferred (200)-oriented structure. The nanocrystallite domain size of the TiN, calculated from peak broadening, was found to be less than 10 nm. No signals from crystalline Si3N4 or other phases of titanium silicide were observed. The hardness of the films, measured using nanoindentation, increased to as much as twice that of pure TiN films.Thin films of Ti–Si–N have been deposited by ionized magnetron sputter deposition using separate Ti and Si targets in an Ar/N2 gas mixture. A built-in rf coil generated an inductively coupled plasma close to the substrate. With this setup, the ion flux and energy can be controlled by adjusting the rf power to the coil and the dc substrate bias. Deposition was carried out under various conditions to investigate the effects of different operational parameters on film structure and mechanical properties. Crystallography, grain size, and film texture have been characterized by x-ray diffraction, showing that the addition of Si to TiN films transforms the (111)-oriented structure to a preferred (200)-oriented structure. The nanocrystallite domain size of the TiN, calculated from peak broadening, was found to be less than 10 nm. No signals from crystalline Si3N4 or other phases of titanium silicide were observed. The hardness of the films, measured using nanoindentation, increased to as much as twice that of pu...