(a) Angle-resolved XPS spectra and fits for N for the hafnium oxynitride sample. The self-consistent analysis of the ARXPS data indicates that the total amount of nitrogen remains constant with RTA. The lower XPS signal for the RTA sample is due to the diffusion of nitrogen to the deeper silicon oxynitride layer upon annealing. The small components with binding at and 401 eV are located at the surface. (b) XPS spectra and fits for O for the hafnium oxynitride sample. The component associated with hafnium oxynitride shifted 0.2 eV to higher binding energy upon RTA, which is consistent with the crystallization shown in the TEM images (Fig. 3 ).
XPS spectra and fits for (a) Si and (b) Hf regions of the hafnium oxynitride sample. The bulk component of Si was aligned to 99.4 eV to correct for band bending (the rest of the data was shifted accordingly).
High resolution TEM images for the (a) unannealed and (b) annealed hafnium oxynitride sample indicating enhanced crystallization upon annealing. (c) The XRD data also show evidence of crystallinity for the hafnium layer of the annealed sample.
Takeoff angular dependence of the peak areas for the unannealed hafnium oxynitride sample. The solid lines are the theoretical prediction using the MLM approach employing the structure represented in the insert and are consistent with the experimental data. The dashed line in the plot for hafnium intensity vs angle dependence provides an example of an inconsistent fit; it is the theoretical prediction of the takeoff angle dependence of Hf assuming that the hafnium layer was at the same depth as the silicon oxynitride.
Takeoff angular dependence of the peak areas for the annealed hafnium oxynitride sample. As in Fig. 4 , the data in open circles correspond to silicon oxynitride and the data in solid squares correspond to hafnium oxynitride. The composition and the thickness depicted in the inserts were obtained from the modeling.
TOF-SIMS data for the unannealed and annealed hafnium oxynitride samples. The overall distribution of Hf–N and Si–N is consistent with the sample structure. It shows the presence of Hf–N bonds in accordance with N substituting O and interacting directly with hafnium. The decrease in the Hf–N counts and the increase in the Si–N counts upon RTA are consistent with the results from the ARXPS analysis.
XPS spectra and fits for N for the hafnium silicate sample. In this case, the component associated with the hafnium layer disappeared upon RTA.
Parameters employed in the angular analysis.
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