Magnetron Sputter Deposition of Amorphous Silicon–SiO 2Quantized Nanolaminates

S. S. Thöny¹, M. Bärtschi², M. Batzer¹, M. Baselgia¹, R. Gmünder¹, A. Sharma³, T. Vermeij³, X. Maeder³, S. Waldner¹

Quantization effects in nanolaminate structures of oxide materials are proposed and experimentally demonstrated only recently. Herein, the material combination of amorphous silicon and SiO₂ deposited by magnetron sputtering is investigated and it is shown that the quantization effect can be observed indeed. Transmission electron microscopy characterization gives evidence of continuous layers of amorphous silicon and SiO₂ with well-defined interfaces. The deposition process is described and the tunability of the refractive index and the bandgap energy is demonstrated. By doing so, the advantages of this novel material over classical optical materials are shown and feasibility is proved. As an example, a longpass optical interference filter with edge at 720 nm is deposited using quantized nanolaminates as the high and SiO₂ as the low refractive index material. This filter can be deposited successfully with close match to the design. It shows a blocking range throughout the visible spectrum whereas a comparable filter based on SiO₂–TiO₂ only blocks 500–700 nm.

¹Evatec AG, Hauptstrasse 1a, 9477 Trübbach, Switzerland
²RhySearch, Werdenbergstrasse 4, 9471 Buchs, Switzerland
³Laboratory for Mechanics of Materials and Nanostructures, Empa, 3602 Thun, Switzerland

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