initially 84 porous example it is believed that the observed densification is due to the creation of strained si o si bonds at neighboring surface sites where oh groups and or methyl groups are removed fig2 b shows an ftir transmission spectra for the porous dielectric of the example after baking in a forming gas surprisingly peaks corresponding to surface species on fig2 a are either sharply reduced or non existent in fig2 b in particular the si oh knee on the si o peak is gone and the combined si o si oh transmission minima shows a 40 transmission where before there was 18 transmission also the ch 3 peak which previously showed 92 transmission now show 98 transmission it is believed that the forming gas treatment removes over 90 of the surface hydroxyls and 75 of the methyl groups on a sample of this type an additional benefit of the forming gas treatment is increased hydrophobicity as disclosed previously the surface modified xerogels are inherently hydrophobic experiments performed on the porous structure before and after the forming gas treatment show increased hydrophobicity as a result of the treatment the invention may also comprise the steps of placing the device in an atmosphere which contains fluorine compounds e g ammonium fluoride hydrogen fluoride fluorine gas which react with the.