Crater edge effects

The sample was analysed with a primary ion beam of extracted from an oxygen cold cathode discharge type source. A well-focussed 200 nA spot was attained at 4keV per molecular ion. The beam was scanned over a square of side 400 pm to produce a uniform primary beam current density and thus a flat-bottomed crater. In order to eliminate crater-edge effects, the counting system was only enabled when the centre of deflection of the beam was in a central area 125 x 125 pm. 

Section 53.232, the analyzed region is made much smaller than the sputtered area to remove crater edge effects and thus to improve depth resolution. 

Even if all possible measures to improve depth resolution are applied, there still exist the effects of the primary ion beam-induced damage experienced by the substrate as a result of the sputtering process. These are discussed in Section 5.3.2.4.1. Crater edge effects and crater base effects can also result in the loss of depth resolution. These are discussed in Sections 5.3.2.4.2 and 5.3.2.4.3, respectively. Dynamic range pertains to the range of concentrations of a specific element or molecule that can be examined in a particular depth profile. As can be envisaged, this depends on the detection limit and on the detector type or combinations thereof (detectors are covered in Section 4.2.3.3). 

In the case of primary ion pulsed Time-of-Fhght-based SIMS instruments, crater edge effects can be removed by rastering the primary ion analysis beam over a smaller region centered within the middle of the primary ion sputter beam raster pattern. 

In another review, Magee and Honig [24] discuss three important aspects of depth profiling by SIMS depth resolution, dynamic range and sensitivity. First, the depth resolution is a measure of the profile quality. They point out that the depth resolution is limited by atomic mixing effects and the flatness of the sputtered crater within the analyzed area. Second, the dynamic range of depth profiles is limited by crater edge... 

Other wear mechanisms are flank wear and crater wear which occur mostly with cemented-carbide tools. Flank wear refers to the depression that is formed below the cutting edge on the side of the tool caused by the abrasive wear of the cemented carbide. TiC is particularly effective in reducing it. Crater wear occurs in the form of small depressions on the rake face behind the point of contact of the tool with the workpiece. Diffusion of the cobalt binder into the cutting chip usually occurs with crater wear. TiN is effective in reducing both diffusion and crater wear.PI... 

Ruby and Nd YAG lasers produce craters ranging from 1 to 500 pm in size. The craters are usually wider than deeper and exhibit overlapping rough materials at the edge suggestive of thermal effects. 

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