Vacuum–ultraviolet pulsed-laser deposition of silicon dioxide thin films

Vacuum–ultraviolet pulsed-laser deposition PLD., using the 157-nm molecular fluorine laser, has been demonstrated to produce particulate-free silica films from a fused silica target, in contrast with the 100-nm particulates found on films grown with the 193-nm ArF laser. XPS analysis has shown that films grown at low laser fluence 3–4 J cmy2 . in 2=10y4 Torr of dry air have significantly improved stoichiometry SiO1.9., relative to films grown in vacuum SiO1.75.. Additionally, for films grown in vacuum, low ablation fluences 3–4 J cmy2.produced films with higher oxygen content SiO1.75. than high ablation fluences )10 J cmy2 peak fluence – SiO1.65.. FTIR has shown that the characteristic Si–O–Si asymmetric stretching mode ASM.absorption peak in the best films grown to date lies at ;1050 cmy1, with a width of 90 cmy1 FWHM., as compared with the 1060–1080 cmy1 position and 70–75 cmy1 width in a high quality thermal oxide. Process optimization and doping with optically-active and -passive ions will permit low-temperature growth of planar optical waveguides for use in optical integrated circuits. q1998 Elsevier Science B.V.