Berlin 2008 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 18: Poster: Towards Molecular Spintronics, Organic Thin Films, Optical Layers, Vibrational Spectroscopy, Tayloring organic interfaces
DS 18.30: Poster
Dienstag, 26. Februar 2008, 14:30–19:30, Poster A
Infrared spectroscopical studies of the evaporation, condensation and annealing process of SiO2 — •Michael Möller, Markus Klevenz, and Annemarie Pucci — Kirchhoff-Institut für Physik, Universität Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg
For several reasons silicon oxides are materials of persistently big interest, from astronomy to microelectronics. We studied the evaporation, condensation and annealing process of SiO2 under ultra-high vacuum (UHV) conditions with in-situ infrared (IR) spectroscopy. All measurements were performed in an UHV chamber with base pressure below 5 × 10−10 mbar. First the equilibrium vapour pressure of quartz (SiO2) was determined by measuring the molecular flow from a tantalum Knudsen cell onto a quartz microbalance. Afterwards the evaporated material was deposited on different substrates with appropriate IR and thermal properties (Si, Ge, Ta). The condensation process was observed with IR transmittance (on Si, Ge) and IR reflectance spectroscopy (on Ta). The observed spectra revealed the optical properties of SiOx with the strongest Si-O stretching vibration bands at 990 and 1125 cm−1. After annealing gradually to temperatures of up to 800∘C a peak shift to 1070 and 1190 cm−1 was observed, respectively, before complete desorption at about 900∘C occurred. The peak shifts can be explained by decomposition of the initial SiOx into Si and SiO2.