Characterization of Ge-doped silica films with low optical loss grown by flame hydrolysis deposition

Ge-doped silica films have been deposited on Si substrates from SiCl4, GeCl4, and H2/O2 by flame hydrolysis deposition (FHD), and annealed to 1150 °C for 2 h. X-ray photoelectron spectroscopy (XPS) showed that the positions of the peaks correspond to the Si, O, Ge, and C levels for Ge-doped SiO2 film. Furthermore, the optical properties of the samples using Variable Angle Spectroscopic Ellipsometry (VASE) illustrate that the refractive index of the samples increase with the increasing GeCl4 flow ratio which indicates that the amount of germanium incorporated into the films increase. We also contrast the refractive indices of samples annealed to different temperatures. When the GeO2 content to SiO2 is equal to 16.28% (the atom ratio of Ge and Si is 10:90), the optical loss of the film is less than 0.527 dB/cm at 1550 nm.