F_2 laser induced oxidation of inorganic material

摘要

Transparent SiO_2 thin films were selectively fabricated on Si wafer by 157 nm F_2 laser in N_2/O_2 gas atmosphere. The F_2 laser photochemically produced active O(~1D) atoms from O_2 molecules in the gas atmosphere; strong oxidation reaction could be induced to fabricate SiO_2 thin films only on the irradiated areas of Si wafer. The oxidation reaction was sensitive to the single pulse fluence of F_2 laser. The irradiated areas were swelled and the height was approximately 500-1000 nm at the 205-mJ/cm~2 single pulse fluence for 60 min laser irradiation. The fabricated thin films were analytically identified to be SiO_2 by the Fourier-transform IR spectroscopy. The SiO_2 thin films could be also removed by subsequent chemical etching to fabricate micro-holes 50 nm in depth on Si wafer for microfabrication.