Secondary electron microscope scanning mode

Fig. 4 Principle of the scanning mode of a secondary electron microscope, where 1, specimen surface 2, detector 3, video processing 4, monitor screen. (From Ref 1)...

Electron Beam Techniques. One of the most powerful tools in VLSI technology is the scanning electron microscope (sem) (see Microscopy). A sem is typically used in three modes secondary electron detection, back-scattered electron detection, and x-ray fluorescence (xrf). AH three techniques can be used for nondestmctive analysis of a VLSI wafer, where the sample does not have to be destroyed for sample preparation or by analysis, if the sem is equipped to accept large wafer-sized samples and the electron beam is used at low (ca 1 keV) energy to preserve the functional integrity of the circuitry. Samples that do not diffuse the charge produced by the electron beam, such as insulators, require special sample preparation. 

The surface analysis for morphology and average particle size was carried out with JEOL JSM 6301 F scanning electron microscope (SEM). The micrographs of the samples were observed at different magnifications under different detection modes (secondary or back-scattered electrons). 

Scanning electron micrographs (SEM) were obtained using a JSM 5500 LV (Jeol, Japan) electron microscope. The observations were performed in a secondary electron (SE) and in a backscattering electron (BSE) mode at a low vacuum pressure of 12 kPa. 

Semicokes prepared in the plastometer were ground, and observed as a dispersion in a Philips EM300 transmission electron microscope or Philips EM400 scanning transmission electron microscope (STEM). The instruments were operated at 100 kV, and the STEM was employed in both the transmitted electron and the secondary electron imaging modes. A portion of each of the samples from the plastometer was reserved for infrared spectra. These spectra were taken on KBr pellets into which a known amount of coal or semicoke was pressed. A spectrum was obtained from each of the coals and from the semicokes from each heat-treatment temperature. All spectra were acquired at room temperature. 

The Pittsburgh No. 8 semicoke that was cooled from 400 C contained remnant mesophase spheres, and these can be seen in Figure 4. This photomicrograph was taken in the secondary electron mode in the scanning transmission electron microscope. 

Experiments. The micro structure of the mortar beams is investigated with a Philips XL 30 FEG Scanning Electron Microscope (SEM). For the analysis in the secondary electrons (SE) mode, freshly broken surfaces are prepared. Polished surfaces are analyzed in the backscattered electrons (BSE) mode. The final polishing stage is carried out with a 1 pm diamond paste. In order to render the mortar surface conductive, samples are coated by evaporation with gold prior to the SEM investigation. 

Rectangular strips of films (ca. 0.5 x 2 mm) were prepared for microscopy as described previously (7). Films were imaged widi a JSM840A scanning electron microscope ( OL, USA, Peabody, MA) in the secondary electron imaging mode at instrument magnifications ranging from 1,OOOX to 10,OOOX. 

Figure 7.28. The image illustrates two different scanning modes of a scanning electron microscope (SEM). In the lower part of the image, we can see the relief of the sample. This is obtained nsing the detection of secondary electrons. In the upper part of the image, we can see light spots surrounded by darker areas. The light spots correspond to the zirconium aggregates in an aluminium matrix. This is obtained using the detection of backscattered electrons.

An FEZ Sirion field emission gun scanning electron microscope (5 Kv) operating in the secondary electron imaging mode was used to examine the surface of the cry-ofractured membranes. Cryofractured surfaces of the dried and swollen samples were examined. 

Samples of the 300-400 and <63p,m fractions were mounted on aluminium pedestals using carbon based double sided tape, and coated with carbon by vacuum evaporation. These were viewed in both secondary electron (SE) and back-scattered electron (BSE) mode using a Camscan series 4 Scanning Electron Microscope. Heavy metal contaminated particles were identified by their high BSE luminescence. Points on individual particles were analysed under the SEM with a Link AM 10,000 Energy Dispersive X-ray Analysis System. The depth of penetration for this method varies with the atomic number,... 

Scanning electron microscopy (SEM) images were captured on a Hitachi 6600 PEG microscope operating in the secondary electron mode and using an accelerating voltage of 1 kV. 

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