Patent attributes
Waveguide structures and methods of fabricating waveguide structures. A first airgap is formed in a bulk semiconductor substrate, and a semiconductor layer is epitaxially grown over the bulk semiconductor substrate and the first airgap. First and second trench isolation regions extend through the semiconductor layer and into the bulk semiconductor substrate, and are spaced to define a waveguide core region including a section of the bulk semiconductor substrate and a section of the semiconductor layer that are arranged between the first and second trench isolation regions. A dielectric layer is formed over the waveguide core region, and a second airgap is formed in the dielectric layer. The first airgap is arranged in the bulk semiconductor substrate between the first trench isolation region and the second trench isolation region and under the waveguide core region. The second airgap in the dielectric layer is arranged over the waveguide core region.
