Keywords:optical waveguide, silicon nitride
In Si photonics, SOI (Si-on-insulator) substrate is usually used in the device fabrication. The use of bulk Si substlate, similar to the erectronic circuits, is promissing in terms of the productivity and the cost. So far, SiNx/SiO2/bulk Si structures have been investigated. In this work, sputtered SiNx layer is shown to be applicable to optical waveguides. From the view point of the integration with Ge photodetectors, an investigation is performed to reduce the thickness of SiO2 undercladding layer.