X-ray photoemission spectra of reactively sputtered TiN

Abstract

X-ray photoemission spectra of reactively sputtered TiN1.0 films are recorded without interference from adsorbed contaminants or ion sputter cleaning damage. In this way, the transition from hcp TiN0.3 to fcc TiN1.0 is characterized by a discontinuity in film stoichiometry, Ti 2p splitting energy, and Ti 2p3/2 binding energy as a function of the Ar/N2 ratio during sputtering. The line shapes of the N 1s and 2s transitions experience only an asymmetric broadening on forming fcc TiN. The core-level N 1s transition of fcc TiN is modeled as two components peaks with binding energies at 396.8 and 396.0 eV. Similarly, the valence band N 2s transition has corresponding component peaks at 16.8 and 16.2 eV. These high and low binding energy pairs are interpreted as on-site Ns and interstitial site Ni populations of nitrogen in a fcc TiN lattice, respectively. The ratio of N/Ti is 1.0 and the Ns/Ni ratio is approximately 6. Both ratios are independent of the composition of the sputtering gas mixture and the substrate temperature once fcc TiN is formed. The core level Ti 2p transition in fcc TiN is characteristic of a single Ti3+ oxidation state with a line shape that is also insensitive to the gas composition and the substrate temperature during sputtering.

Preparation of photoactive nitrogen-doped rutile

“…The main maximum is placed at 396.1 eV and it is accompanied with a small shoulder at about 399 eV. The former position of N 1s peak is ascribed in the literature to the different states of atomic nitrogen associated with the presence of oxygen [40], titanium oxynitride [41,42] or interstitial nitrogen [43]. The small feature at 399 eV can originate from C N bonds usually coming from carbon contamination.…”

Ti substituted nano-crystalline Cu3N thin films

“…Also, when Ti is sputtered in an N 2 atmosphere, the sputtering yield is decreased because a part of Ti on the target surface is nitrided. 33 This effect is weaker for the Cu because it is more difficult to nitride Cu than Ti due to weaker Cu-N bonding. After being sputtered for some time the Ti:Cu ratio on the target surface will reach an equilibrium so that the ratio of the sputtered yield of the two materials are less than their ratio in the bulk target.…”

Cyclic Nanoindentation and Nano-Impact Fatigue Mechanisms of Functionally Graded TiN/TiNi Film

“…The fact that a short-time sputtering eradicated these small peaks indicates that they are from surface contaminants. There is a peak at 395.7 eV which can be attributed to the binding energy of nitrogen atoms in interstitial tetrahedral position in TiN lattice [41]. The ratio between on-site N in TiN lattice and interstitial N was found to vary from 6/1 to 7/1, indicating most nitrogen atoms are in the TiN lattice.…”

“…As shown in Fig. 1d, the detailed deconvolution of Ti components in the TiN surface layer is quite difficult because there could be overlapping among different components [30,[40][41][42][43][44]. However, the dominant Ti 2p and Ti 2p 3/2 peaks in the TiNi layer are linked with metallic Ti states in the TiNi phase, and the binding-energy values are slightly lower than those of the Ti 2p peaks in the TiNi phase.…”

“…The second region presents the composition of TiN layer in which the atomic ratio of Ti over N is about 1.2-1.5:1. It should be noted that XPS has a better sensitivity for determining low concentrations of nitrogen, oxygen and carbon elements, but underestimates their amounts at higher concentrations [40][41][42]. During sputtering process, effects such as preferential sputtering of different atomic species may take place.…”