Structures of Micro Films of TiN by Ab-initio Calculation: Implication to X-ray Absorption Near Edge Structure (XANES)

XANES (X-ray Absorption Near Edge Structure) of TiN and TiO2 layers on various substrates have been investigated by comparing the theoretical L3,2 edge of titanium and K edges of nitrogen and oxygen of various crystals, including TiN, TiO, and hcp Ti. The theoretical work is based on the relativistic spin-polarized density functional theory with generalized gradient approximation. XANES spectra of these crystals have been numerically evaluated using a full-potential linearized augmented plane wave (FPLAPW) method. The wave function used in this calculation is the superposition of radial wave function and spherical harmonics Ylm in the atomic Muffin tin region, and is a Fourier expansion in the interstitial region, with matched atomic boundary condition. These results have been compared to the experimental results of Ti L-edges and N K-edges, of various thin TiNx films on Si(100) substrates and a micro-sandwiched film of 400DAl/300DTiNx/Si(100). The nitrogen K-edge shows excellent agreement between theory and experiment. The oxidation of TiNx films is evident from the Ti L-edge spectra as they are compared to the calculated spectra.