Berlin 2001 – wissenschaftliches Programm

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AMPD: EPS AMPD

AMPD 1: Sitzung 1

AMPD 1.2: Vortrag

Montag, 2. April 2001, 11:30–11:55, H105

Slow ion collisions at insulator surfaces - the role of potential projectile energy — •Friedrich AUMAYR — Institut f. Allgemeine Physik, TU Wien, A-1040 Wien, Austria

Since during the last two decades intense sources for slow, highly charged ions (HCI) have become available, the possibility of exploiting the huge amount of potential energy stored in such projectiles for surface modification and nanofabrication has captured the imagination of researchers. Applications have been envisioned, ranging from information storage via material processing to biotechnology. Compared to kinetic sputtering (i.e. sputtering of target atoms due to momentum transfer in collision cascades), which unavoidably causes unwanted radiation damage in adjacent regions, sputtering induced by the potential energy of slow highly charged ions (termed potential sputtering - PS) holds great promise for a more gentle nanostructuring tool. A profound understanding of the mechanisms responsible for the conversion of projectile potential energy in such PS processes is therefore highly desirable. PS phenomena have been reported by several groups for a variety of insulator target surfaces as, e.g., alkali-halides, SiO2, UOx, GaAs, mica and hydrocarbon-contaminated surfaces (see, e.g., [1 - 3] and references therein). These investigations have in common that a dramatic increase of the total sputter yields, the secondary ion emission yields and/or the size of single ion - induced surface defects have been observed with increasing projectile charge state. We summarize a series of systematic experiments in which PS has been investigated with hyperthermal singly and multiply charged ions impinging on Au, LiF, NaCl, SiO2, Al2O3, and MgO, and discuss the mechanisms leading to potential sputtering as well as the minimum potential energy necessary to induce PS [4].

This work has been carried out within Association EURATOM-ÖAW and was supported by Austrian FWF.

[1] M. Sporn, et al., Phys. Rev. Lett. 79, 945 (1997).

[2] F. Aumayr, et al., Comm. At. Mol. Phys. 34, 201 (1999).

[3] T. Schenkel et al., Progr. Surf. Sci. 61, 23 (1999).

[4] G. Hayderer, et al., Phys. Rev. Lett. 83, 3948 (1999).