Ion-beam analysis

The application of ion beam analysis techniques to determine pore size and pore volume or density of thin silica gel layers was first described by Armitage and co-workers [114]. These techniques are non-destructive, sensitive and ideally suited for the analysis of thin porous films such as membrane layers (dense support is needed for backscattering). However, apart from a more recent report on ion-beam analysis of sol-gel films [115] using Rutherford backscattering and forward recoil spectrometry, ion beam techniques have not been developed further despite their potential for membrane characterisation. This is probably due to the limited availability of ion beam sources, such as charged particles accelerators. 

This method, using a microfocused beam, has unique advantages over other techniques which could be very useful in membrane characterisation. Thus in the above work examples of measurements made on gel layers as a function of sampling depth (from 3 pm to 100 pm) and as a function of distance across the sample were illustrated. It will also be noted that the technique is equally appropriate for measurements in the micro and mesoporous ranges. 

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Figure Bl.24.1. Schematic diagram of the target chamber and detectors used in ion beam analysis. The backscattering detector is mounted close to the incident beam and the forward scattering detector is mounted so that, when the target is tilted, hydrogen recoils can be detected at angles of about 30° from the beam direction. The x-ray detector faces the sample and receives x-rays emitted from the sample.

Chaimelling only requires a goniometer to inelude the effeet in the battery of MeV ion beam analysis teelmiques. It is not as eonnnonly used as tire eonventional baekseattering measurements beeause the lattiee loeation of implanted atoms and the aimealing eharaeteristies of ion implanted materials is now reasonably well established [18]. Chaimelling is used to analyse epitaxial layers, but even then transmission eleetron mieroseopy is used to eharaeterize the defeets. 

In this section, a number of applications for NRA are presented. As this is not a review article, the following is only a sampling of the possible uses of this powerful technique. The reader interested in information on additional applications is directed to the proceedings of the Ion Beam Analysis Conferences and those from the International Conferences on the Application of Accelerators in Research and Industry, among other sources. 

Nuclear reactions are excited when projectile energies are typically in the MeV range. Medium size ion-accelerators are, therefore, necessary to obtain these projectile energies. Protons and a projectiles, typical projectiles in other ion-beam analysis techniques as RBS or PIXE, have few useful nuclear reactions. Deuteron beams excite many more nuclear reactions, but the use of deuteron beams instead of standard beams is more hazardous, because of efficient neutron production. Strict safety rules are necessary when high-energy deuteron beams are used. 

M. Nastasi (eds.) Handbook of Modem Ion Beam Analysis, Materials Research Society, Pittsburgh 1995, p. 83. 

Principles and Characteristics Particle-induced X-ray emission spectrometry (PIXE) is a high-energy ion beam analysis technique, which is often considered as a complement to XRF. PIXE analysis is typically carried out with a proton beam (proton-induced X-ray emission) and requires nuclear physics facilities such as a Van der Graaff accelerator, or otherwise a small electrostatic particle accelerator. As the highest sensitivity is obtained at rather low proton energies (2-4 MeV), recently, small and relatively inexpensive tandem accelerators have been developed for PIXE applications, which are commercially available. Compact cyclotrons are also often used. 

Although following similar nuclear reaction schemes, nuclear analytical methods (NAMs) comprise bulk analysing capability (neutron and photon activation analysis, NAA and PAA, respectively), as well as detection power in near-surface regions of solids (ion-beam analysis, IB A). NAMs aiming at the determination of elements are based on the interaction of nuclear particles with atomic nuclei. They are nuclide specific in most cases. As the electronic shell of the atom does not participate in the principal physical process, the chemical bonding status of the element is of no relevance. The general scheme of a nuclear interaction is ... 

The characteristics of radiochemical methods are well known [435]. An overview of the determination of elements by nuclear analytical methods has appeared [436]. Some selected reviews of nuclear methods of analysis are available charged particle activation analysis [437,438], instrumental neutron activation analysis [439-441] and ion-beam analysis [442]. 

Ion Beam Analysis (IBA) utilizes high-energy ion beams to probe the elemental composition of the surface of a specimen in a non-destructive way. It can establish the composition as a function of depth to several microns, with a typical depth resolution of 10-20 nm. It is a fast and standardless technique which quantifies the absolute atomic ratios, and can also determine the film thickness. 

HIBS is the same as RBS, except that heavy ions are used instead of He++. It is an ion beam analysis tool patented by the Sandia Corporation of the USA, and was developed to enable the measurement of trace levels of surface contamination on silicon wafers. Metal contamination present in starting material is detrimental to devices, since it results in defects which limit wafer yields and impair circuit operation. 

Grime, G.W. (1999) High energy ion beam analysis methods (and background) , in Encyclopaedia of Spectroscopy and Sprectrometry Ed. J.C. Lindon, G.E. Tranter J.L. Holmes, Academic Press, Chichester, pp. 750-760. 

Abraham, M. (2004), Ion beam analysis in art and archaeology, Nuclear Instrum. Meth. Phys. Research B 219-220, 1-6. 

Figure 16.3 Schematic layout of the AMS beam line at LABEC in Florence. Note that the system is also equipped with two independent ion sources dedicated to Ion Beam Analysis and with a switching magnet with six measurements beam lines (not shown)...

The ion-beam analysis techniques described in preceding sections have been applied in many investigations of hydrogen in semiconductors. In this section we will mention studies in two areas where ion-beam analysis of H has made a significant contribution these are the thermal release and redistribution of implanted hydrogen and the absolute measurement of IR absorption cross sections in a-Si H. In addition, we will mention a developing field, the study of hydrogen in interfaces. 

As a second example of the application of ion-beam analysis techniques to semiconductors, we take the calibration of IR absorption measurements of the hydrogen content of sputtered amorphous silicon and silicon nitride. In early measurements, the hydrogen content of glow-discharge a-Si H deduced from IR absorption measurements, using ablsinitio calculations of the absorption cross section of the Si—H IR absorption bands, was com-... 

Maenhaut W. Applications of ion beam analysis in biology and medicine, a review. Nucl Instr Methods B 1988 35 388-403. 

Salamanca, M.A. O., Ruvalcaba-Sil, J. L., Bucio, L., Manzanilla, L., and Miranda, J. (2000). Ion beam analysis of pottery from Teotihuacan, Mexico. Nuclear Instruments and Methods in Physics Research B 161 762-768. 

Della Mea, G. Dran, J.-C. Petit, J.-C. Bezzon, G. Rossi-Alvarez, C., paper presented at 6th Ion Beam Analysis Meeting, Tempe, Arizona, 1983-... 

See the proceedings of the following International Conferences appeared in special issues of Nuclear Instruments and Methods in Physics Research Section B Nucl. Instrum. Methods Phys. Res. B 2002, 193, Proc. of the 19th Intern. Conf. on Atomic Collisions in Solids Nucl. Instrum. Methods Phys. Res. B 2002,190, Proc. of the I5th Intern. Conf. on Ion Beam Analysis Nucl. Instrum. Methods Phys. Res. B 2001, 175-177, Proc. of the 12th Intern. Conf. on Ion Beam Modification of Materials Nucl. Instrum. Methods Phys. Res. B 2001,18I, Proc. of the 7th Intern. Conf. on Nuclear Microprobe Technology and Applications. 

The field of materials analysis by energetic ion beams has begun to mature in the last decade after arising within the nuclear physics community. The basic method, Rutherford back-scattering, has been the subject of a text (1 ), and the field has also engendered a useful handbook (2). Publications are scattered throughout the literature with much of the output in articles relating to the properties of materials. In these the ion beam analysis may form only a part of the work. New developments in technique and applications continue and have been the subject of a series of international conferences (see for example (3) for the latest of these). 

First, because of the large energy difference, this method is completely insensitive to chemical binding effects. While other conventional surface analysis techniques which are sensitive to the chemical state are unquestionably frequently required, it is also true that methods thus dependent on the chemical state may suffer from difficulties in calibration, particularly in transition regions where an element is found in more than one chemical state. Energetic ion beam analysis, on the other hand, offers an absolute technique independent of these effects. As such, this technique and other conventional techniques (e.g. Auger, ESCA etc.) may often prove to be complementary, each supplying information not available by the other techniques. 

Third, the requirement of accelerating an ion to the MeV range of energies must necessarily entail a larger size, more expensive and often more complex acceleration apparatus. Thus, the technique of energetic ion beam analysis grew in the... 

The use of elastic backscattering, which is the primary technique for energetic ion beam analysis, is the normal method of choice when it will produce satisfactory results. Some other ion beam techniques which may be useful in supplementing backscattering in specific cases will be discussed later in this paper. 

Conference on Ion Beam Analysis" (Sydney, Australia, 16-20 February 1981) to be published in Nucl. Instrum. Methods. 

Positive Aspects of Low Energy Ion Beam Analysis Methods... 

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