Waveguides with multiple airgaps arranged in and over a silicon-on-insulator substrate

摘要

Waveguide structures and methods of fabricating waveguide structures. The waveguide structures are formed using a semiconductor substrate that includes a device layer, a handle wafer, a buried oxide layer between the handle wafer and the device layer, and an epitaxial semiconductor layer over the device layer. First and second trench isolation regions extend through the device layer and the epitaxial semiconductor layer. The first and second trench isolation regions are spaced to define a waveguide core region comprising a section of the device layer and a section of the epitaxial semiconductor layer that are arranged between the first and second trench isolation regions. A first airgap and a second airgap are respectively located in the device layer and the buried oxide layer. The first and second airgaps are arranged beneath the waveguide core region, and the first airgap may be arranged between the second airgap and the waveguide core region.