LOW-PRESSURE CHEMICAL VAPOR-DEPOSITION SILICON-OXYNITRIDE FILMS FOR INTEGRATED-OPTICS

The low-pressure chemical vapor deposition of silicon-oxynitride films for applications as integrated optical waveguides on silicon substrates, using gas compositions of SiH2Cl2-NH3-N2O, SiH2Cl2-NH3-O2, and SiH4-NH3-O2, has been investigated with respect to deposition rate, uniformity, reproducibility in the 1.46-2 index range, and propagating loss. The best results were obtained with the SiH2Cl2-NH3-O2 reaction, which provides a deposition rate up to 30 nm/min and a thickness variation across a wafer below 3% at propagation losses below 0.5 dB/cm.