A study of titanium nitride diffusion barriers between aluminium and silicon by X-ray absorption spectroscopy: the Si, Ti and N results

Abstract

We report a multi-elment, multi-edge and multi-detection mode X-ray photoabsorption study of a series of Al/TiN(x)/Si(100) thin films as a function of the TiN(x) film thickness (100A-500A) and of the annealing temperature (400 degrees C-600 degrees C). The Si K- and L-edge results show that Si does not diffuse to the surface for all the films. The high resolution Ti L-edge and N K-edge spectra show that the TiN(x) layer undergoes a dramatic chemical reaction with the gradual increase in the annealing temperature. This chemical reaction stabilizes at 560 degrees C at which the TiN(x) film is known to fail to act as an effective diffusion barrier between Al and Si.

Synthesis and study of highly dense and smooth TiN thin films

“…6 (b) the four features marked as 'f ' (Ti 2p3/2→O2pπ+Ti3d), 'g' (Ti 2p3/2→O2pσ+Ti3d), 'h' (Ti 2p1/2→O2pπ+Ti3d) and 'i' (Ti 2p1/2→O2pσ+Ti3d) can be assigned to L 3 -t 2g L 3 -e g , L 2 -t 2g and L 2 -e g transitions which arise due to the octahedral crystal field splitting [38]. But surprisingly the 2p spin-orbit coupling in all samples are found to be ≈ 5.5 eV which is in well agreement with that of surface oxidation free TiN films where a caping layer of Al was used to avoid surface contaminations [67]. However, spectral modifications is quite often in Ti L-edge spectra due to the multiplet effect which plays a dominant role for early transition metal nitride films like TiN [38].…”

“…To get an idea about the spin-orbit coupling, the Ti L-edge features were also studied. Here, it is worth mentioning that Ti L-edge consists of two features (L 3 and L 2 ) which arises due to the transition of core electron from Ti 2p3/2→Ti 3d and Ti 2p1/2→Ti 3d respectively [67]. Although, our obtained Ti L-edge features are not consistent with the literature reports [67,68] and clearly confirms the presence of surface oxidation which was in accordance with our XRR fitting.…”

Unraveling the Origin of Visible Light Capture by Core–Shell TiO2 Nanotubes

“…More concrete evidence is provided at the N Kedge XANES in Figure S7, where the presence of a Ti−N bond is demonstrated both on the surface and in the bulk of NNT, whereas no Ti−N bond is observed on the surface of NNT450 and trapped N 2 is shown in the bulk. 41 As for the crystalline core of NNT, although it displays a similar anatase structure with NNT450 and NT450, as revealed by PFY XANES (Figure 4b and Figure S3b), the decrease of the density of Ti unoccupied states in the bulk of NNT (Figure S4b and d) still shows its different electronic nature (e.g., oxygen-deficient TiO 2 ) from the other two. Hence, we further characterized the bulk of NNT, NNT450, and NT450 using bulk-sensitive resonant inelastic X-ray scattering (RIXS).…”

“…The area ratio of substitutional N peak to the interstitial N peak for NNT is ∼1.24, and this ratio decreases to ∼0.72 for NNT450, suggesting that substitutional doping is dominant in NNT whereas interstitial doping prevails in NNT450. More concrete evidence is provided at the N K-edge XANES in Figure S7, where the presence of a Ti–N bond is demonstrated both on the surface and in the bulk of NNT, whereas no Ti–N bond is observed on the surface of NNT450 and trapped N 2 is shown in the bulk …”

Total electron yield mode for XANES measurements in the energy region of 2.1–6.0 keV

“…X-ray absorption near edge structure (XANES) spectroscopy is a widely used tool to elucidate local coordination environment and chemistry of the absorbing atom [1][2][3][4]. XANES is the region of an X-ray absorption spectrum within ∼50 eV of the absorption edge.…”