Molybdenum depth profile

Fig. 23. Depth profile of nitrogen in molybdenum after 91 h of nitriding at 645 °C under the same conditions as given in Fig. 22. During the measurement the surface was sputter etched by Ar+ bombardment and the composition continuously monitored by Auger spectroscopy194 ...

Depth profiles are usually presented as atomic concentrations versus sputter time, assuming we know the rate at which the sample sputters. A typical depth profile is shown in Figure 25. It is interesting to see that at the surface there is carbon, silicon dioxide and some molybdenum. As soon as the surface layer is sputtered off (300 A), the oxygen and carbon impurities drop to constant and small values. For this CVD film, the molybdenum silicide came out to be very silicon rich. We can also see that the stoichiometry of the silicide changed with position (depth) in the film. 

Figure 25 Auger depth profile of molybdenum silicide film.

Thin Films. SIMS depth profiles are also used In the development of new thin film processes. These processes are being Investigated to produce higher speed and greater device density In VLSI applications. Molybdenum metal gates are being Investigated... 

In a related study, the deposition of molybdenum silicide from a composite target was compared to that cosputtered from elemental targets (42). SIMS depth profiles showed that the concentration of carbon and argon was lower and the level of oxygen was higher In the cosputtered film. Sheet resistance and C-V measurements for both types of films were also compared and were found to be not grossly different. 

Figure 18. Quantitative oxygen depth profiles in pure (A) and contaminated (B) molybdenum disulfide coatings. a.s recorded by nuclear reaction analysis.

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