Development of Si/SiO2 super-lattices deposited by RF reactive sputtering

We report on the progress that has been made on the realisation of narrow spectrum photonic crystal filters operating in the communications band. The development of a process for the deposition of silicon–silicon dioxide super-lattices using RF reactive sputtering is described. The use of reactive sputtering of silicon dioxide from a silicon target enables a much higher deposition rate than could be achieved using a SiO2 target. The characteristics of these films are shown to closely match the widely accepted values for silicon dioxide over a wide range of wavelengths. The cross-sectional SEM micrograph of a super-lattice deposited in this manner is presented which shows clearly the alternating layers with well-defined interfaces.