Abstract: Methods are provided for depositing insulator material at a pre-defined area of an integrated circuit (IC) by: placing an IC in a vacuum chamber; applying to a localized surface region of the integrated circuit at which insulator material is to be deposited a first gas containing molecules of a dissociable compound comprising atoms of silicon and oxygen and a second gas containing molecules of a compound which reacts with metal ions; generating a focused ion beam having metal ions of sufficient energy to dissociate molecules of the first gas; and directing the focused ion beam at the localized surface region to dissociate at least some of the molecules of the first gas and to thereby deposit on at least a portion of the localized surface region a material containing atoms of silicon and oxygen. The dissociable compound comprises atoms of carbon and hydrogen, such as di-t-butoxydiacetoxy-silane. The compound which reacts with metal ions may be carbon tetrabromide or ammonium carbonate.