Planar optical waveguide thin films grown by microwave ECR PECVD

Optical thin films of silicon dioxide were deposited from an electron cyclotron resonance SiH4/O2/Ar plasma onto a radio frequency biased substrate at a pressure of a few 10−1 Pa, 100 W microwave power (f=2.45 GHz) and low wafer temperature (<120°C). The optical and structural properties of films were characterized using FTIR, XPS, AFM, STM and multicolor ellipsometry. The relationship between the growth rates and deposition parameters was investigated and the characterizations of the films with a rf substrate bias were compared to those without bias. Furthermore, 1.17% of Ge-doped silica films were successfully deposited by feeding into GeCl4. The concentration of Ge could be precisely controlled to satisfy the requirements of different planar optical waveguides and devices.