Ion beams, generation

Ion-Assisted Processes An alternative use of ion beams generated from low cost sources is to assist particular chemical reactions, or vapour deposition. An example here is in etching processes (Figure 16). The simultaneous use of an argon beam with XeFp gas compared with the use of either separately, to etch silicon produces an etch rate of a factor of at least fourteen. The use of ion beams can also increase the directionality (23) of the process (Figure 17). Examples are given in Table IV of how ion bombardment during film formation modifies the final film. 

Because ion-beam treatment effect on the electrical properties of the wafers is independent of the treatment temperature and ion type, one of the mechanisms of this influence is the formation of point defects. This can lead to (i) the positive charge creation in the surface oxide layer [2] (ii) transfer of boron atoms into the electrically inactive interstitial positions by the ion-beam generated Sii atoms... 

Besides El, Cl, FI or FD techniques for generating ions in the mass spectrometer, some other ionization techniques have been reported. One such technique is metastable atom bombardment (MAB), which Is based on Penning ionization. In MAB a metastable ion beam generated outside the ion volume is used to bombard the sample. The energy available for ionization is discrete (quantified) and can be fixed by the choice of the rare gas used in the atom gun (He, Ne, Ar, Kr, Xe). This energy ranges from 8 to 20 eV. 

Figure 8.19 SIMS images of ceramic coating on titanium obtained with scanning ToF SIMS. Ga+ primary ion beam generates the positive ion images of Ca, Ti, O and OH. Chemical gradients of O and OH in the coating layer (left-hand sides of images) are revealed.

Nikolaev VS, Dmitriev IS (1968) Phys Lett A 28 277 Osipovicz T, Breeze MBH, Watt F, van Kan JA, Bettiol AA (eds) (2007) Nud Instrum Methods B 158 1-482 Prczesky VM, Przybylowicz WJ, Pineda CA (eds) (1999) Nucl Instrum Methods B 158 1-735 Rajta I, Kiss AZ, Kertesz Zs, Szikszai ZA, Simon A (eds) (2009) Nucl Instrum Methods B 267 1995-2340 Reijonen J (2000) Plasma and ion beam generation using RF and microwave ion sources. PhD dissertation, University Jyvaskyia, Finland RFQ (2003) http //hsbpcl.ikf.physik.uni-frankfurt.de/ ezr/rfq.htm... 

Commercial instrumentation often employs a combination of some form of a Faraday cup along with a high-gain electron multiplier detector. This combination permits both high-intensity ion beams, generated by high-concentration major constituent determinations, along with low-concentration trace element determinations. 

Avdic A, Lugstein A, Schondorfer C, Bertagnolli E (2009) Eocused ion beam generated antimony nanowires for microscale pH sensors. Appl Phys Lett 95(22) 223106-223103... 

Computers will be integrated more and more into commercial SEMs and there is an enormous potential for the growth of computer supported applications. At the same time, related instruments will be developed and extended, such as the scanning ion microscope, which uses liquid-metal ion sources to produce finely focused ion beams that can produce SEs and secondary ions for image generation. The contrast mechanisms that are exhibited in these instruments can provide new insights into materials analysis. 

The Duoplasmatron (Eig. 3.18). In the Duoplasmatron, gas-discharge ion sources are used for bombardment with oxygen or argon. In dynamic SIMS, especially, the use of O2 ions is common because of the chemical enhancement effect. With a duoplasmatron ion beam currents of several microamps can be generated. The diameter of the beam can be focused down to 0.5 pm. 

Figure 8. Schematic outline of a second-generation MC-ICPMS instrument (Nu Instalments Nu Plasma), equipped with a multiple-Faraday collector block for the simultaneous measurement of up to 12 ion beams, and three electron multipliers (one operating at high-abundance sensitivity) for simultaneous low-intensity isotope measurement. This instmment uses zoom optics to obtain the required mass dispersion and peak coincidences in place of motorized detector carriers. [Used with permission of Nu Instruments Ltd.]...

Figure 9. Schematic diagram showing a second-generation MC-ICPMS instrament (ThermoFinnigan Neptune). This instrument utilizes double-focusing and is equipped with a motorized multiple-Faraday collector block with two channels that can be operated in high-resolution mode. Optional multiple-ion counting channels are also available for the simultaneous measurement of low-intensity ion beams. [Used with permission of Thermo Finnigan.]...

Principles and Characteristics In metastable atom bombardment (MAB), a metastable atom beam, generated by a gun external to the ion volume, is used to bombard the sample. MAB, based on Penning ionisation, offers unique features for gas-phase ionisation. The energy available for ionisation and fragmentation is discrete (excitation energy of the atom, from 8 to 20 eV),... 

Particle-induced X-ray emission (PIXE) in which electrons are ionised, and elemental specific X-rays are generated by the incident ion beam. 

Particle-induced gamma-ray emission (PIGE) in which nuclei are excited and gamma-rays are generated by the ion beam. 

Simulation spectra were generated using parameters that describe the ion beam, target and detector geometry, beam and detector resolution, and sample characteristics. The sample parameters, which include the number of layers and the areal density and atomic composition of each layer were then varied until the simulation conformed to the experimental data. The HIBS spectra were analysed using a modified version of the RBS analysis program. 

The Physical Electronics 680 Nanoprobe employs a field emission electron gun, and this results in a spatial resolution of less than lOnm. Ion bombardment for depth profiling is available in the SAM, and both the electron beam and the ion beam are computer controlled so that depth profiles can be run automatically, and maps and line scan of Auger electron distributions can be generated. 

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