Integration of CMOS devices on to glass substrates has many process constraints. One of these is the melting point of the substrate, which is much lower than silicon. Normally a thermal oxide is desired for use as the gate dielectric, but at the lower temperature constraints due to the substrate it is not possible. One potential solution to this is they use of fluorine as an oxidation enhancement source is the ambient.
Silkey, Brian R.
"The Role of Fluorine in Growth Rate Enhancement and Charge Supperssion on a Low Temperature Thermally SiO2 Interface Layer,"
Journal of the Microelectronic Engineering Conference: Vol. 18
, Article 19.
Available at: http://scholarworks.rit.edu/ritamec/vol18/iss1/19