Regensburg 2010 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 9: Poster: Synthesis of Nanostructured Films by Self-organization, Thermoelectric Thin Films and Nanostructures, High-k and Low-k Dielectrics, Layer Deposition Processes, Layer Growth, Layer Properties, Application of Thin Films, Surface Modification, Hard and Superhard Coatings, Metal Layers

DS 9.29: Poster

Montag, 22. März 2010, 15:00–17:30, Poster D1

Spectroscopic Characterisation of Amorphous Silicon Thin Films — •Philipp Schäfer¹, Frank Nobis², Hartmut Kupfer², Frank Richter², and Dietrich R. T. Zahn¹ — ¹Semiconductor Physics, Chemnitz University of Technology — ²Solid State Physics, Chemnitz University of Technology

Amorphous Silicon (a-Si) and especially hydrogenated amorphous silicon is widely used in photovoltaic applications. Despite its lower total efficiency compared to crystalline silicon, a-Si has the advantage of cheaper and easier proccessing. It can be deposited at low temperatures, it is mechanically flexible, and it provides technically relevant films already at sub-micrometre film thicknesses. However, an elaborated understanding of the film properties is required in order to improve the preparation parameters.

In this work d.c.-pulsed magnetron sputtered a-Si films are probed with various spectroscopic techniques. Thus, a comprehensive picture of their properties is achieved: Raman spectroscopy provides access to the morphological aspects of the film. One can distinguish between microcrystalline, crystalline, and amorphous films. Furthermore, it allows a detailed morphological characterisation of amorphous film in terms of the spread in mean bond angle Δ θ to be obtained. Fourier transform infrared spectroscopy, on the other hand, reveals the concentration of hydrogen. Variable angle spectroscopic ellipsometry is applied and the complex dielectric function ε (ν) of the a-Si layer is evaluated using a Tauc-Lorentz model. A detailed comparison of a-Si layers prepared under various sputtering conditions is provided.