Silicon provides a natural substrate base for the development of channel waveguides and their integration with optoelectronic components. Using epitaxial growth, selective doping, and plasma etching, channel waveguides can be fabricated using single crystal silicon alone. Oxide layers of low optical index are readily formed by thermal means on silicon to provide a base upon which low-loss film waveguides can be formed by ion exchange and implantation, chemical vapor deposition, and physical vapor deposition. Thermally oxidized and nitrided layers provide a simple means for developing waveguides. The channel shape for ridge waveguides can be delineated by chemical etching and ion milling techniques. The anisotropic etch characteristics of silicon provide a natural channel for imbedding waveguides using organic and inorganic materials. This paper will review common semiconductor processing techniques used for the formation of channel waveguides on silicon and the performance results obtained to date. The use of channel waveguides for specific device developments will be described and the most promising areas for future development will be addressed.
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