Damage depth distribution

Another basic approach of CL analysis methods is that of the CL spectroscopy system (having no electron-beam scanning capability), which essentially consists of a high-vacuum chamber with optical ports and a port for an electron gun. Such a system is a relatively simple but powerful tool for the analysis of ion implantation-induced damage, depth distribution of defects, and interfaces in semiconductors. ... 

Fig. 11.5. The damage depth distribution obtained from an analysis of ion channeling data...

In addition to the generation of platelets, hydrogenation of silicon also induces electronic deep levels in the band gap. As in the case of platelet formation, these defects are considered to be unrelated to either plasma or radiation damage because they can be introduced with a remote hydrogen plasma. Comparison of depth distributions and annealing kinetics of the platelets and gap states has been used to a limited extent to probe the relationship among these manifestations of H-induced defects. 

Conventional. In most of the laboratories around the world, TEM specimens are usually prepared in a conventional manner that shews only the "plan" view of the damage distribution, i.e., the plane of the foil being parallel to the inplanted or otherwise processed surface. Although much useful information concerning defect structures and their nature can be obtained, the depth distribution of defects is difficult to ascertain even from stereo microscopy. This is especially true in cases vtere either two or more discrete layers of defects separated ty a defect free region are present or vhere the defects of interest are buried under another more dense band of defects. Therefore,... 

A.G.J. Buma, M.K. de Boer, P. Boelen (2001). Depth distributions of DNA damage in Antarctic marine phyto- and bacterioplankton exposed to summertime ultraviolet radiation. J. PhycoL, 37, 200-208. 

Fig. 8.10. (a) The 1.8-MeVHe backscattering spectra for random and (110) aligned Si crystal before and after damage by a 5 x 1014 cm-2, 200-keV B implant at -150°C. (b) The analyzed depth distribution of the disorder and the deposited energy into atomic collisions normalized to the disorder profile at a depth of 5,500 A (after Feldman et al. 1982)... 

Fig. 11.8. The ion implantation damage distribution co-plotted with the H depth distribution. The dashed vertical lines represent the range in the measured Ion-Cut cleavage depth as determined by XSEM, AFM and XTEM...

Besides the ion range or damage range distribution associated with ion/solid interactions there is also the depth distribution for the sputtered particles. This distribution is sharply peaked at the sample surface so that most of the sputtered atoms come from the top monolayer. For a light atom in a heavy matrix this value is believed to be somewhat larger. This result is predicted by Sigmund s (15) theory. For sputtered atoms from a metallic target that are ionized, i.e., those that are used in SIMS, their depth distribution is more sharply peaked in the top monolayer because of the efficient neutralization processes that occur for ions created below the top monolayer. 

For characterizing the corrosion damage due to pitting one measures the depth distribution of pits. From such data the evolution of maximum pit depth with time or the time to perforation can be estimated using statistical methods [23,24]. Because pitting is a random process the observed pit depth depends on the surface area taken into account. The depth L has been found to vary according to a power law (7.25) or a logarithmic law (7.26) where A is the surface area and K (i = 1,2. .) are constants. 

As sputtering removes atoms/molecules present at the outer surface of a solid and damage is of minor concern (opposite to Static SIMS), measurement of the secondary ion signal as a function of sputtering time provides the depth distribution of the signal measured. In other words, the removal of atoms from the outer surface that occurs during SIMS analysis exposes deeper layers, which then become part of subsequent analyzed populations. Profiles over depths ranging from several nm up to 10 pm can then be collected. Under ideal conditions, the depth resolution can surpass 1 run. 

A diagnosis of possible damage should be made before beginning repairs with other construction measures [48,49]. There should be a checklist [48] of the important corrosion parameters and the types of corrosion effects to be expected. Of special importance are investigations of the quality of the concrete (strength, type of cement, water/cement ratio, cement content), the depth of carbonization, concentration profile of chloride ions, moisture distribution, and the situation regarding cracks and displacements. The extent of corrosion attack is determined visually. Later the likelihood of corrosion can be assessed using the above data. 

Static SIMS is appropriate for obtaining information on the lateral distribution of surface chemical species. A broad, defocussed ion beam is often used in order to minimise surface damage. In dynamic SIMS sample erosion takes place quite rapidly, and depth profiles are obtained by monitoring peak intensities in the mass spectrum of sputtered ions as bombardment proceeds. 

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