Laser annealing of phosphosilicate glass

Laser annealing of CVD layers of phosphosilicate glass (PSG) using a CO2 laser (10.6 μm wavelength) has been investigated. Evidence of plastic flow of the PSG caused by laser heating was obtained. Reduction of surface and bulk defects in the PSG layers was ascertained by measurement of scattering losses, before and after annealing, of He–Ne radiation (632.8 μm) waveguiding in the layers. An improvement in attenuation of as much as 12 dB/cm was obtained.