Preparation and characterization of SiO2–B2O3–P2O5 particles and films generated by flame hydrolysis deposition for planar light-wave circuits

Abstract

Boron-phosphosilicate glass particles were deposited on Si wafer by flame hydrolysis deposition under controlled conditions. A few ten nanometer sized and spherical glass particles were synthesized in an oxy-hydrogen flame. The wafer surface temperature of 500 °C proved sufficient to form the Si–O–B framework while a higher temperature (approximately 730 °C) was required to produce Si–O–P formation. Gaussian bands at 3242 cm−1 provided evidence that the dissolved B2O3 concentration increased with the substrate temperature. In as-deposited porous films, a certain quantity of crystalline B2O3 remained, which was completely transformed into the noncrystalline phase after post deposition annealings. Film density measurements indicated that the B2O3 content in the doped silica films would be substantially lower than that in the precursor mixture.