Syntheses and optical properties of low-temperature SiOx and TiOx thin films prepared by plasma enhanced CVD

SiOx, TiOx and SiOx-TiOx mixed thin films were prepared by PEC VD at a subs trate temperature below 80 degrees C using tetraethoxysilane (TEOS) and eth yltrimethylsilane (ETMS) for SiOx and titaniumtetraisopropoxide (TTIP) for TiOx, respectively. Optimal deposition conditions for preparing SiOH free E TMS SiOx are control of the external magnetic field and use of Ar as a exci tation gas. The refractive index of SiOx increased with the ratio of infrar ed absorption intensity of Si-C to that of Si-O, which is related to the st oichiometry of SiOx determined by Si-O-Si stretching absorption frequency a nd XPS analysis. The refractive index (n) of SiOx varied from 1.459-1.559 w ith extinction coefficient (k) lower than 3.0 x 10(-4). This index of TiOx was from 1.750-2.047 and k lower than 2.0 x 10(-3). The refractive index of mixed SiOx-TiOx thin film can be varied from 1.460-1.820 by controlling fr action constituents content. (C) 1998 Elsevier Science Ltd. All rights rese rved.