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DS: Dünne Schichten
DS 30: Ionenimplantation III
DS 30.3: Fachvortrag
Thursday, March 30, 2000, 11:30–11:45, H31
Irradiation induced chemical reaction and mixing in Ni3N/Al and Ni3N/Si bilayers — •S. Dhar1, L. Rissanen1, K.-P. Lieb1, K. Engel2 und M. Wenderoth2 — 1II. Physikalisches Institut und SFB 345 — 2IV. Physikalisches Institut, Universität Göttingen, 37073 Göttingen.
Thin ceramic films of nitrides, oxides and carbides are most indispensable constituents in modern silicon based devices and coating technology. Therefore, the knowledge of their bonding properties with metals and semiconductors under ion irradiation are of great practical importance specially for space and reactor applications. In this report, we present the experimental results on the irradiation effects induced by 100-700 keV Xe+ ions at 80 K on the surface and interface of Ni3N/Al and Ni3N/Si bilayers. Ni3N layers of 70-100 nm thickness were deposited via reactive magetron sputtering. The ion fluence was varied from 0.5 to 4x1016 ions/cm2. The samples were characterised by RBS, RNRA using the 15N(p,αγ) reaction, XRD and AFM techniques. The preferential nitrogen loss in the near surface region and an increase in surface roughness have been observed after irradiation at all fluences. Surface roughness increases approximately linearly with the ion fluence. After 450 keV Xe ion irradiation, we observe a solid state reaction at the interface of Ni3N/Si leading to the formation of Ni2Si and Si3N4 phases. In contrary, only strong mixing but no phase formation in Ni3N/Al system was found. In both cases, the experimental mixing rates cannot be explained by pure collisional cascade mixing. These results illustrate the competition of ballistic mixing and chemical driving forces at the bilayer interface.