Tantalum depth profile

In order to carry out depth profiling with AES, the sputtering rate must be determined. The sputtering rate is usually measured by determining the time required to sputter through a layer of known thickness. Anodized tantalum foils are convenient for this purpose since the oxide thickness can easily be controlled and since the interface between the metal and the oxide is relatively sharp [43]. 

Figure 7.14 Depth profiles of the 3-to-2 photon ratio for plain silica Xerogel and versions that include tantalum (blue upward triangles) or iron (green downward triangles). In the plain and tantalum case, positronium can move far through the open sponge like network of channels. This is reduced dramatically for the case of embedded iron. The line stems from a fit to extract the escape depth of 880 nm.

Figure 3 shows a depth profile of tantalum silicide on silicon. The sputter rate Is approximately 200A/mln. In this example, the Interface can be easily Identified at a sputter time of ten minutes. Figures 4 is the Ta 4f photoelectron region prior to the start of sputtering (spectrum a) and after five minutes (spectrum b). 

Figure 3. Depth profile of tantalum silicide on silicon.

Figure 7 Depth profiles of (A) niobium and (B) tantalum in the western North Pacific (45°N 165°E Sohrin ef a/., 1998).

F ure 329 AES depth profile of a 30-nm-thick tantalum oxide fikn on tantalum, prepared by anodization (adapted from ref. [8]). 

The glow discharge optical spectroscopy (GDOS) of the A 301L sample indicated the coating composition (Figs.7,8). The results of the depth profile analysis proved carbon enrichment in the interface of the steel substrate and the tantalum layer. 

Fig. 11. SEM micrograph of cross-sectional structure and TbF-SIMS depth profiling data of tantalum oxide films grown for different times, (a) Close-up of the edge of a partially detached 5 min oxide film, (b) Depth profile of a film grown for 1 min. (c) Depth profile of a film grown for 10 min. (d) Depth profile of a film grown for 20 min. (Reproduced with permission from Ref. 76. Copyright 2008 American Chemical Society.)...

---