Structural properties of fluorinated SiO2 thin films

✍ Scribed by Fabio Iacona; Giuseppina Casella; Francesco La Via; Salvatore Lombardo; Vito Raineri; Giuseppe Spoto

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 115 KB
• Volume: 50
• Category: Article
• ISSN: 0167-9317
• DOI: 10.1016/s0167-9317(99)00266-x

✦ Synopsis

Fluorinated SiO (SiOF) films, prepared by plasma enhanced chemical vapour deposition from SiH , N O and CF 2 4 2 4 precursors, have been analysed by infrared (IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) to extract chemical and structural information. Notwithstanding XPS reveals that fluorine concentrations are quite low (less than 4 at.%), the analysis of the Si-O-Si vibration modes in the IR spectra indicates that CF addition involves a deeper 4 modification of the film structure, than the simple formation of Si-F bonds. In particular, by increasing the F concentration in the oxides, the stretching frequency of the Si-O-Si bonds increases, while the bending frequency decreases. On the basis of the central force model, both observations are consistent with the occurrence of a Si-O-Si bond angle relaxation phenomenon, the importance of which increases with the fluorine concentration in the films.