Double-strip-shaped silicon nitride waveguide and preparation method thereof

Abstract

The invention discloses a double-strip-shaped silicon nitride waveguide and a preparation method thereof. The waveguide comprises a silicon substrate; a first SiO2 coating layer which is uniformly coated on the upper surface of the silicon substrate; a double-strip-shaped Si3N4 waveguide structure which is located on the upper surface of the first SiO2 coating layer, wherein the double-strip-shaped Si3N4 waveguide structure is wrapped by a second SiO2 coating layer; the preparation method comprises the following steps: forming a first SiO2 coating layer on a silicon substrate through a thermaloxidation process; sequentially growing a Si3N4 layer / an alphaSi layer / a Si3N4 layer; forming an alphaSi / Si3N4 double-strip-shaped silicon nitride waveguide structure through photoetching / ion beam etching; partially removing the alpha Si material in the interlayer by wet etching, and thermally oxidizing the left alpha Si to form SiO2 by using the high-temperature oxidation resistance of the silicon nitride material; and finally, growing a second SiO2 coating layer by using a PECVD process, thereby manufacturing the double-strip silicon nitride waveguide.

Description

technical field [0001] The invention relates to the technical field of optical materials, in particular to a double-strip silicon nitride waveguide and a preparation method thereof. Background technique [0002] An optical waveguide is a dielectric device that guides light waves to propagate in it, also known as a dielectric optical waveguide. Among them, silica waveguide is a very common and important kind of PLC optical waveguide material, which is generally prepared by planar optical waveguide technology. [0003] The manufacturing process of conventional silica optical waveguide is as follows: [0004] 1) Use flame hydrolysis (FHD) or chemical vapor deposition (CVD) to grow a layer of SiO on the silicon wafer 2 , which is doped with phosphorus and boron ions as the lower cladding of the waveguide; [0005] 2) Use FHD or CVD process to grow another layer of SiO on the lower cladding layer 2 , as a waveguide core layer, which is doped with germanium ions to obtain the ...

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Problems solved by technology

[0012] In order to solve the above-mentioned technical problems, one of the objects of the present invention is to provide a double-strip silicon nitride waveguide, which forms a vertical double-strip waveguide structure, which solves the problem of directly etching the dielectric material SiO2 in the traditional process. 2 The problem of low verticality

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