Dresden 2006 – scientific programme

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DS: Dünne Schichten

DS 17: Ion beam solid interaction II

DS 17.4: Talk

Thursday, March 30, 2006, 12:00–12:15, GER 37

Ion beam enhanced etching of LiNbO₃ — •Thomas Gischkat¹, Frank Schrempel¹, Holger Hartung², Ernst-Bernhard Kley², and Werner Wesch¹ — ¹Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, D-07743 Jena, Germany — ²Institut für Angewandte Physik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, D-07743 Jena, Germany

Single crystals of z-cut and x-cut LiNbO₃ were irradiated at room temperature and 15 K using 350 keV Ar⁺-ions with ion fluences between 5×10¹² and 1×10¹⁵ cm⁻². The damage formation investigated with RBS channeling analysis depends on the crystal cut as well as the irradiation temperature. Irradiation of z-cut material at 300 K provokes complete amorphisation at 0.4 dpa (displacements per target atom). In contrast 0.27 dpa are sufficient to amorphise the x-cut LiNbO₃. Irradiation at 15 K reduces the number of displacements per atom necessary for amorphisation to 0.18 dpa. To study the etching behavior 400 nm thick amorphous layers were generated via multiple irradiation with Ar⁺-ions of different energies and fluences. Etching was performed in a 3.6% HF-solution at 40 ^∘C. Whereas the etching rate of the perfect crystal is negligible, that of amorphised regions amounts to 80 nm min⁻¹. The influence of the ion fluence, the irradiation temperature and subsequent thermal treatment on damage and etching of LiNbO₃ is discussed.

In conlusion, negligible etching of the perfect crystal, high etching rates and high contrast of Ion Beam Enhanced Etching (IBEE) allow the realisation of high aspect ratio microstructures in LiNbO₃.