Influence of fluorine doping on SiOxFy films prepared from a TEOS/O2/CF4 mixture using a plasma enhanced chemical vapor deposition system

Influence of F incorporation into the SiO2 matrix was studied during SiOF film deposition using a conventional r.f. plasma enhanced chemical vapor deposition technique from a mixture of TEOS/O2/CF4. With increasing CF4 flow rate from 0 to 70 sccm, the fluorine content in the film varied from 0 to 5.5 at.% and the refractive index decreased from 1.46 to 1.41. In addition, SiF2 bonds with hydrophile property were identified in the SiOF films deposited at CF4 flow rates above 50 sccm. In the Fourier transform infrared spectroscopy spectra of these films, however, the SiOH and OH absorption bands were hardly observed, indicating that these films have a strong resistance to water absorption. From the electron microscopy investigation and the analysis of optical spectra, it was also confirmed that all the SiOF films studied were homogeneous and had a dense and amorphous structure without micro-pores.