Scanning electron microscope auger electrons

If an incident electron beam of sufficient energy for AES is rastered over a surface in a manner similar to that in a scanning electron microscope (SEM), and if the analyzer is set to accept electrons of Auger energies characteristic of a particular element, then an elemental map or image is again obtained, similar to XPS for the Quantum 2000 (Sect. 2.1.2.5). 

Modem instmments use all of these signals to extract information about a sample. These include the scanning electron microscope, the transmission electron microscope, the electron microprobe, and the auger nanoprobe. For many of these techniques, a conductive... 

The spatial resolution of scanning Auger microprobe systems Is now equivalent to most scanning electron microscopes. High magnification secondary electron Images or absorbed current images are a routine part of the data from such systems. Quantitative Aspects of AES... 

K IxlO 7 torr of oxygen was added to the vacuum system to remove carbon contamination and keep the particle clean. Sample cleanliness was examined by rcannealing the sample in a PHI 660 Scanning Auger Microprobe (SAM). The panicle starts out with a rounded shape and no distinct structure. When the sample is annealed in vacuum, the particle is convened to a nearly spherical shape with a series of flat facets. Electron channeling patterns taken in the scanning electron microscope indicate that the larger facets are oriented in the (100) direction while the smaller facets... 

In the case of AEAPS, it is not necessary to detect individual Auger peaks, as the total secondary electron yield can be measured instead. The electron cascade within the material can act as an electron multiplier increasing the AEAPS signal. Hence an REA could be used or an electron detector of a type used in a scanning electron microscope. 

Scanning Auger Electron Spectroscopy (SAM) and SIMS (in microprobe or microscope modes). SAM is the most widespread technique, but generally is considered to be of lesser sensitivity than SIMS, at least for spatial resolutions (defined by primary beam diameter d) of approximately 0.1 im. However, with a field emission electron source, SAM can achieve sensitivities tanging from 0.3% at. to 3% at. for Pranging from 1000 A to 300 A, respectively, which is competitive with the best ion microprobes. Even with competitive sensitivity, though, SAM can be very problematic for insulators and electron-sensitive materials. 

Over the past decade increasing use has been made of the scanning transmission electron microscope (STEM) for examining catalysts(20). Owing to the increased efficiency with which scattered electrons and associated signals such as X-rays, secondary and Auger electrons may be collected, the STEM offers greater analytical flexibility compared with the CTEM (21). 

Some of the techniques described in this chapter used most widely today are Auger electron spectroscopy, X-ray photoelectron spectroscopy, electron-probe micro-analysis, low energy electron diffraction, scanning electron microscope, ion scattering spectroscopy, and secondary ion mass spectroscopy. The solid surface, after liberation of electrons, can be analyzed directly by AES, XPS, ISS, and EPMA (nondestructive techniques), or by liberation of ions from surfaces using SIMS (involving the destruction of the surface). Apart from the surface techniques, reflectance-absorbance infrared (RAIR) spectroscopy has also been employed for film characterization (Lindsay et al., 1993 Yin et al., 1993). Some... 

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