Surface Modification by Ion Implantation

DOROTHEE M. RUCK Gesellschaft fiir Schwerionenforschung mbH. Darmstadt. Germany 

Ion implantation is a technique that involves the introduction of ionized atoms with high energies into the surfaces of metals, ceramics, semiconductors and polymers in order to modify their surface properties. Due to the high energies of the ions practically any element can be implanted in a near-surface substrate layer, and limited solubilities are not a problem. New compounds and alloys can be formed, leading to changes in the properties of a surface that can be divided arbitrarily into chemical (e.g., etchability and corrosion), physical (e.g.. optical, conductivity and wettability), and mechanical (e.g.. hardness, wear and strength), properties. 

Although the method of ion implantation has been introduced into industrial processes, especially in the semiconductor industry and for the treatments of tools, there is a prevailing need to improve the understanding of the underlying physics. 

Three international conferences exist in which the latest fundamental results and the developments in the technique are presented and discussed, namely Ion Beam Modification of Materials (IBMM), Surface Modification of Met- 

Polymers are sensitive to ionizing radiation and can be modified with low ion doses. In addition to the fundamental aspects of structural changes, there are several application-related investigations under way. In the electronics packaging industry and for the protective coating of metals [45, 46], the problem of adhesion between metal and polymer may be solved by ion irradiation [47]. Electrical properties such as conductivity as well as the optical properties of polymers can be modified, and as a result investigations in the field of passive optical devices are in progress [48-50]. 

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Guzman, L., Celva, R., Miotello, A., Voltolini, E., Ferrari, R, Adami, M. (1998) Polymer surface modification by ion implantation and reactive deposition of transparent films. Surf Coat. Tech., 103-104,375-379. 

Picreaux, S., and Pope, L., Tailored Surface Modifications by Ion Implantation and Laser Treatment, Science, 226 615-622 (1986)... 

Surface modification by ion implantation, which involves the introduction of ionized species (virtually any element) into the substrate using a beam of high-velocity ions... 

In a recent communication [91], Ni surface alloyed with Cu, Ti, or Cu + Ti by ion implantation was examined for its redox and electrocatalytic activities by cyclic voltammetry. The surface was characterized by XPS, x-ray, and electron diffraction, as well as by electron and atomic force microscopies. This type of material exhibited a unique voltammetric response of Ni and was shown to stabilize the / -modification of the Ni oxide/hydroxide. It was demonstrated that the morphology and microstructure differ from those of bulk materials. 

Ion implantation This study involves modifying the surface of nanofiltration membranes by ion implantation for increased salt rejection [55]. ions at two different intensities—lElO and 5E10 atoms/cm —were implanted on the surface of commercially available nanofiltration membranes to increase the negativity of the membrane surfaces. The objective was to increase the Donnan exclusion effect to improve salt rejection by the modified membranes. It was also noted that this modification did not significantly damage the semipermeable membrane surface. 

Technological process of the PS based composite structures is illustrated schematically in Fig. 1. The process starts with the PS host formation and then, if wanted, the modification of PS can be performed. The second step is filling the PS pores with a material or coating formation on the PS surface. The final step consists of different treatments (e.g. aimealing, oxidation) to obtain a desired stmcture. The process sequence can be changed if filling materials are introduced into Si by ion implantation [5] before the porosification. Moreover, the process can be shortened if... 

Modification of Ti-6A1-4V alloy surfaces by ion implantation with iridium, at fluences of 0.74 x 10 and 1.48x10 ions/cm, corresponding to 2.5 and 5.0 at% Ir peak concentrations, has been reported (Buchanan... 

Sioshansi P. (1987) Surface modification of industrial components by ion implantation. 

In this section a number of selected examples coming from different areas of possible application are discussed. The reasons why these examples have been chosen is that all the investigations have been carried out in collaboration with those research institutes and industrial companies that have a particular application or end product already in mind that could be achieved by ion implantation modification. The examples illustrate how certain classes of surface and interface problems arising from industrial and/or technical requirements can be solved by ion implantation methods. 

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