Beam sources sputtering

We have recently commissioned a new reflected beam Cs sputter source [6] to be used in these experiments. This source is better suited to this work than the old non-reflecting source, as the Cs beam is focussed to sputter ions off a very small pill or plug of material. This gives an ion beam with good optical properties (since the source spot size is small) and allows the use of very small samples. We are currently working with samples of 1-5 mg of BeO or graphite. 

All carbon samples could easily be oxidized to C02, a form of the sample greatly preferred by most users, for many reasons. Neither the on-line or dedicated electrostatic accelerators under construction have succeeded in overcoming the problem of too much memory of C02 gas. Consequently, the sample presented to the cesium sputter beam source will probably have to be a solid. The cesium sputter source is the most likely to be used because it can produce negative ions of carbon in microampere beams. 

Secondary ion sources (using primary ion beams to sputter solid sample surfaces) are applied not only in SIMS and SNMS, but also for the formation of negative ions in accelerator mass spectrometry (AMS). 

Effects of Primary Beam Species Prediction of FABMS source sputtering yields can be generally supported by available data on secondary ion emission coefficients. For secondary ions detected at zero angle with respect to the surface normal, the secondary ion emission yield generally increases with the mass of the primary ions because of the... 

Fig. 11.1. The scheme of the setup for composite film deposition by ion-beam sputtering of the compound target (1) substrate holder with heater (2) substrate (3) ion-beam source (4) shutter.

Fig. 11.2. The scheme of the setup for composite film preparation with separate sputtered targets and a multiple hearth electron-beam source (1) substrate holder (2) substrates (3) water-cooled copper crucibles (4) electron-beam guns.

Molecular beam sources for use at high collisional energies have also employed the methods of charge exchange [41], sputtering [42] and rotor beams [43]. Pulsed metal beams have been generated by the novel method of the evaporation of a metal film by a high power pulsed laser [44],... 

The principles of ion sources which use a primary ion beam for sputtering of solid material on sample surface in a high vacuum ion source of a secondary ion mass spectrometer or a sputtered neutral mass spectrometer are shown in Figure 2.30a and Figure 2.30b, respectively. Whereas in SIMS the positive or negative secondary ions formed after primary ion bombardment are analyzed, in SNMS the secondary sputtered ions are suppressed by a repeUer voltage and the sputtered neutrals which are post-ionized either in an argon plasma ( plasma SNMS ), by electron impact ionization ( e-beam SNMS ) or laser post-ionization are nsed for the surface analysis (for details of the ionization mechanisms see references 122-124). 

Furthermore the system is fully automated, self-tuning and needs little or no maintenance. The operator will consider the instmment as an analytic tool the fact that an accelerator is involved is incidental. Up to 50 solid graphite samples can be loaded in a carousel prior to analysis. COj samples can be admitted on line to the ion source. The ion source uses a primary caesium beam to sputter the sample under investigation to form a negative carbon ion beam. The ion beam is accelerated through the system to reach the detector with an energy of 2.5 MeV. A detailed description of the system can be found in Nucl. Instr. and Meth. B123 (1997) 159. 

A typical AMS instrument is shown in Figure 7.10. It consists of five main units an ion source, an ion-extraction and acceleration system, an MeV accelerator, a mass analyzer, and an ion-detection system. In the ion source, negative ions are formed by bombarding the sample with a Cs" ion beam. The sputtered ions are extracted at 10 to 20 keV into a two-stage mass filter for the separation of isotopes. The mass-selected negative ions (e.g.,... 

By working principle, they can be classified as hot filament sources, ion sources based on Penning discharge (PIG), radio frequency (RF) and microwave (MW) ion sources, electron cyclotron resonance (ECR) ion sources, electron beam ion sources (EBIS, EBIT), laser ion sources, cusp and multicusp ion sources, sputtering ion sources. 

High-quality films of TCOs have been fabricated by ion beam sputtering from oxide targets [173, 201] at deposition temperatures less than 100 °C. Fan [201] has used an argon-ion beam source with a typical value of current of 50 mA. 

The Bendix mass spectrometer must be considered a commercial success, since many of these instruments can still be found in industrial and academic laboratories throughout the United States. In later years, manufacture of these instruments was taken over by CVC Products (Rochester, NY), which continued to produce the model 2000 until a few years ago. An attractive feature of the Bendix instruments seems to have been the ease with which they could be modified for specific applications. In 1962, Lehrle et al. replaced the electron beam in the Bendix ion source with an ion beam source that could be used to generate either ions or neutrals with kinetic energies in the range of 0 to 2 keV. While used primarily for studies of gas-phase ion-molecule or neutral-molecule reactions, it was also further modified to enable sputtering of surfaces. Shortly after the introduction of chemical ionization by Field and Munson in 1966, Futrell et al. described a modified ion source for... 

The fonnation of clusters in the gas phase involves condensation of the vapour of the constituents, with the exception of the electrospray source [6], where ion-solvent clusters are produced directly from a liquid solution. For rare gas or molecular clusters, supersonic beams are used to initiate cluster fonnation. For nonvolatile materials, the vapours can be produced in one of several ways including laser vaporization, thennal evaporation and sputtering. 

Harper J M E, Cuomo J J and Kaufman H R 1982 Technology and applications of broad-beam ion sources used in sputtering. Part II. Applications J. Vac. Sc/. Technol. 21 737-56... 

Radiation Sources. Ordinarily, electron beams are produced from soHds in vacuo by thermal or field-assisted processes. Plasmas also serve as electron sources, but are more uniquely used as ion sources. Whereas ions can be produced by sputtering and field assisted processes in the absence of plasmas, most ion sources involve plasmas (75). 

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