Amorphous-Nanocrystalline Transition in Silicon Thin Films Obtained by Argon Diluted Silane PECVD

Rachid Amrani, Frederic Pichot, Larbi Chahed, Yvan Cuminal

Département de Physique, Université d’Oran ES-Sénia, Oran, Algérie.
Université Montpellier II, Place Eugène Bataillon Montpellier, Montpellier, France.

DOI: 10.4236/csta.2012.13011                

Abstract

The Plasma-Enhanced Chemical Vapor Deposition (PECVD) method is widely used compared to other methods to deposit hydrogenated silicon Si:H. In this work, a systematic variation of deposition parameters was done to study the sensitivities and the effects of these parameters on the intrinsic layer material properties. Samples were deposited with 13.56 MHZ PECVD through decomposition of silane diluted with argon. Undoped samples depositions were made in this experiment in order to obtain the transition from the amorphous to nanocrystalline phase materials. The substrate temperature was fixed at 200^oC. The influence of depositions parameters on the optical proprieties of the thin films was studied by UV-Vis-NIR spectroscopy. The structural evolution was also studied by Raman spectroscopy and X-ray diffraction (XRD). The structural evolution studies show that beyond 200 W radio frequency power value, we observed an amorphous-nanocrystalline transition, with an increase in crystalline fraction by increasing RF power and working pressure. The deposition rates are found in the range 6 - 10 /s. A correlation between structural and optical properties has been found and discussed.

Keywords

Silicon Thin Film; PECVD; Amorphous-Nanocrystalline Transition; Deposition Rate; Powders; Argon

Conflicts of Interest

The authors declare no conflicts of interest.

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