Ion-bombarded surfaces

Insertion of impurities Superconductivity of bombarded metals Variations of thin film properties Wear, friction and lubrication of materials Wear, friction and lubrication of materials Chemical state of implanted atoms Reactivity of ion-bombarded surfaces Reactivity of ion-bombarded surfaces Ionization phenomena Charge exchange studies... 

As oxygen adsorbs on the nickel surface, the intensity of the diffraction pattern from the nickel lattice decreases because of the low penetrating power of the electrons. This rate of decrease with increasing exposure is approximately the same for an ion-bombarded surface which has been well annealed as for one which has received a small anneal. However, the diffraction patterns from the gas-lattice structures on the surface with the small anneal are much more intense than those from the gas-lattice structures on the well-annealed surface because of the different defect densities in the two cases. If the extinction of the pattern from nickel were caused by the presence of the gas-lattice structures, one should expect a greater rate of extinction for the surface having a small anneal. Since this is not the case, the major part of the ex-... 

For the hydrogenation of ethylene, the activities of nickel and platinum were observed after various surface treatments of argon-ion bombardment, radiation cooling, and annealing (38). Activities for the ion bombarded surfaces were as great as 10 times those for annealed surfaces while those for the radiation-cooled surfaces were 2-3 times the annealed values, thus indicating the role of lattice defects in this type of reaction. 

Water and Methanol The interaction of H20 with the (100) surface of MgO prepared by polishing and ion-bombarded single-crystal surfaces has been studied using X-ray photoelectron spectroscopy (XPS) both before and after annealing at 900 K (Onishi et al., 1987). It was observed that at room temperature water did not adsorb on the annealed surfaces. However, ion-bombarded surfaces did display features of OH-, presumably due to the creation of surface defect sites allowing water adsorption. At 200 K, both the polished and ion-bombarded surfaces showed evidence of OH- after exposure to H20, the ion-bombarded surface being covered with a monolayer of OH- (Peng and Barteau, 1990, 1991). 

The present work indicates, in the case of bombarded nickel, that defects in some form appear to exist after 140 hrs. of annealing at room temperature. The distorted structure of an ion-bombarded surface as observed by low-energy electron diffraction and the known presence of argon in this structure (referred to above) indicate that the defects produced by bom-... 

Such disadvantages clearly do not exist when the dominating neutral particle flux from an ion bombardment surface is evaluated. Even when the usually... 

Garrison BJ, Winograd N, Harrison DE (1979) Ejection of molecular clusteas fiom ion-bombarded surfaces. J Vac Sci Technol 16 789-792. doi 10.1116/1.570087... 

Auger electron spectroscopy AES Electron emission from surface atoms excited by electron. X-ray, or ion bombardment Surface composition... 

Figure 8.9 Radius of curvature increased from 50mm to 2000mm using ion bombardment surface treatment. (Reprinted with permission from J. Microelectromechanical Systems, Elimination of stress-induced curvature in thin-film structures, 1967 IEEE.) [19].

Figure 3.4.1.18 RAS and STM results of clean Cu(llO) surfaces. (I) Wide atomically flat (1x1) terraces, (ii) anisotropic stepped surface with (1x1) terraces, (ill) ion-bombarded surface, and (iv) mechanically polished in air. Adapted from Ref [135].

Once a sample is properly oriented and polished, it is placed into a UHV chamber for the final preparation steps. Samples are processed in situ by a variety of methods in order to produce an atomically clean and flat surface. Ion bombardment and aimealing (IBA) is the most conunon method used. Other methods include cleaving and film growth. 

Dodonoy A I, Mashkova E S and Molchanov V A 1989 Medium-energy ion scattering by solid surfaces. Ill ejection of fast recoil atoms from solids under ion bombardment Rad. Eff. Def Sol. 110 227-341... 

Abrams C F and Graves D B 1998 Energetic Ion bombardment of SIOj surfaces molecular dynamics simulations J. Vac. Sc/. Technol. A 16 3006-19... 

Sputtered Neutral Mass Spectrometry (SNMS) is the mass spectrometric analysis of sputtered atoms ejected from a solid surface by energetic ion bombardment. The sputtered atoms are ionized for mass spectrometric analysis by a mechanism separate from the sputtering atomization. As such, SNMS is complementary to Secondary Ion Mass Spectrometry (SIMS), which is the mass spectrometric analysis of sputtered ions, as distinct from sputtered atoms. The forte of SNMS analysis, compared to SIMS, is the accurate measurement of concentration depth profiles through chemically complex thin-film structures, including interfaces, with excellent depth resolution and to trace concentration levels. Genetically both SALI and GDMS are specific examples of SNMS. In this article we concentrate on post ionization only by electron impact. 

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