Vertical mirror in a silicon photonic circuit
First Claim
1. A method for forming a mirror in a silicon photonic circuit, comprising:
- providing a handle wafer;
forming a buried oxide (BOX) layer on the handle wafer;
providing a device wafer comprising a silicon on insulator (SOI) wafer on the BOX layer;
depositing a nitride layer on the device wafer;
etching a trench in the device wafer to expose the BOX layer;
etching the BOX layer to create an undercut beneath the device layer;
immersing in an etchant to fill the trench creating a trapezoidal shape from the trench and undercut areas with the device layer comprising a facet;
depositing and reflowing a thick oxide layer in the trench; and
replanerizing the device wafer, wherein the facet comprises a re-entrant total-internal-reflection (TIR) mirror.
1 Assignment
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Accused Products
Abstract
A vertical total internal reflection (TIR) mirror and fabrication thereof is made by creating a re-entrant profile using crystallographic silicon etching. Starting with an SOI wafer, a deep silicon etch is used to expose the buried oxide layer, which is then wet-etched (in HF), opening the bottom surface of the Si device layer. This bottom silicon surface is then exposed so that in a crystallographic etch, the resulting shape is a re-entrant trapezoid with facets These facets can be used in conjunction with planar silicon waveguides to reflect the light upwards based on the TIR principle. Alternately, light can be coupled into the silicon waveguides from above the wafer for such purposes as wafer level testing.
12 Citations
15 Claims
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1. A method for forming a mirror in a silicon photonic circuit, comprising:
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providing a handle wafer; forming a buried oxide (BOX) layer on the handle wafer; providing a device wafer comprising a silicon on insulator (SOI) wafer on the BOX layer; depositing a nitride layer on the device wafer; etching a trench in the device wafer to expose the BOX layer; etching the BOX layer to create an undercut beneath the device layer; immersing in an etchant to fill the trench creating a trapezoidal shape from the trench and undercut areas with the device layer comprising a facet;
depositing and reflowing a thick oxide layer in the trench; andreplanerizing the device wafer, wherein the facet comprises a re-entrant total-internal-reflection (TIR) mirror. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification