Low loss high-k slot waveguides for silicon photonics

Silicon photonic integrated circuits are promising solutions for high speed on-chip data communication. Producing crystalline silicon optical waveguides at the backend of the IC process flow requires wafer-bonding and a deep substrate etching of an SOI wafer. Fabrication of optical interconnects is less complex and more cost effective if deposited amorphous silicon can be used instead. Amorphous silicon on the other hand suffers from a high absorption. Slot waveguide is a suitable solution for integration of alternative materials with silicon waveguides. Active devices with slot waveguides have been reported by Ramirez et al where the slot layer is doped with rare-earth metals to generate light. In this work successful fabrication and characterization of CMOS compatible low loss high-k amorphous silicon slot waveguides is reported.