<p>This Thesis treats the growth and characterization of ternary transition metal nitride thin films. The aim is to probe deeper into the Ti-Al-N system and to explore the novel Sc-Al-N system. Thin films were epitaxially grown by reactive magnetron sputtering from elemental targets onto single-crystal substrates covered with a seed layer. Elastic recoil detection analysis and Rutherford backscattering spectroscopy were used for compositional analysis and depth profiling. Different x-ray diffraction techniques were employed, ex situ using Cu radiation and in situ during deposition using synchrotron radiation, to identify phases, to obtain information about texture, and to determine the thickness and roughness evolution of layers during and after growth. Transmission electron microscopy was used for overview and lattice imaging, and to obtain lattice structure information by electron diffraction. Film properties were determined using van der Pauw measurements of the electrical resistivity, and nanoindentation for the materials hardness and elastic modulus. The epitaxial M<sub>n+1</sub>AX<sub>n</sub> phase Ti<sub>2</sub>AlN was synthesized by solid-state reaction during interdiffusion between sequentially deposited layers of (0001)-oriented AlN and Ti thin films. When annealing the sample, N and Al diffused into the Ti, forming Ti<sub>3</sub>AlN at 400 ºC and Ti2AlN at 500 ºC. The Ti<sub>2</sub>AlN formation temperature is 175 ºC lower than earlier reported results. Ti<sub>4</sub>AlN<sub>3</sub> thin films were, however, not possible to synthesize when depositing films with a Ti:Al:N ratios of 4:1:3. Substrate temperatures at 600 ºC yielded an irregularly stacked Tin+1AlNn layered structure because of the low mobility of Al adatoms. An increased temperature led, however, to an Al deficiency due to an out diffusion of Al atoms, and formation of Ti<sub>2</sub>AlN phase and Ti<sub>1-x</sub>Alx<sub>N</sub> cubic solid solution. In the Sc-Al-N system the first ternary phase was discovered, namely the perovskite Sc<sub>3</sub>AlN, with a unit cell of 4.40 Å. Its existence was supported by ab initio calculations of the enthalpy showing that Sc3AlN is thermodynamically stable with respect to the binaries. Sc3AlN thin films were experimentally found to have a hardness of 14.2 GPa, an elastic modulus of 21 GPa, and a room temperature resistivity of 41.2 μΩcm.</p>
| Identifer | oai:union.ndltd.org:UPSALLA/oai:DiVA.org:liu-17683 |
| Date | January 2009 |
| Creators | Höglund, Carina |
| Publisher | Linköping University, Linköping University, Thin Film Physics, Linköping : Linköping University Electronic Press |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Licentiate thesis, comprehensive summary, text |
| Relation | Linköping Studies in Science and Technology. Thesis, 0280-7971 ; 1344 |
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