Grating Coupler and MOS Modulator Rib Structure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The manufacturing of MOS optical modulators using a SOI substrate with rib waveguides is complex and costly, and there is a need for improved characteristics and grating coupler performance.
Innovation Solution
A semiconductor device is fabricated with a grating coupler and MOS optical modulator on a silicon platform, featuring a rib structure with projections and slab portions formed from successively stacked semiconductor and insulating layers, reducing production costs and enhancing performance by optimizing the structure and etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MOS optical modulator is manufactured using SOI substrate with rib waveguide, then optical modulation function is achieved, but manufacturing complexity increases and production cost rises
Solution Approach 1:
The patent segments the manufacturing process into distinct etching stages: first etching the second semiconductor layer to form gratings, then etching the first semiconductor layer to form rib waveguides. This segmentation allows each layer to be processed independently with optimized parameters, reducing overall manufacturing complexity while maintaining optical modulation functionality.
Solution Approach 2:
The patent performs preliminary etching of the second semiconductor layer to create grating structures before forming the rib waveguides in the first semiconductor layer. This preliminary action establishes the optical coupling structures first, which then guide the subsequent rib waveguide formation, simplifying the overall process sequence and reducing manufacturing steps.
2Reliability
If MOS optical modulator is manufactured using SOI substrate with rib waveguide, then optical modulation function is achieved, but production cost increases
Solution Approach 1:
The patent merges the formation of gratings and rib waveguides into a single etching sequence without requiring intermediate deposition or patterning steps. The grating structures in the second semiconductor layer and rib waveguides in the first semiconductor layer are created through coordinated etching operations, reducing the total number of manufacturing steps and lowering production cost while maintaining optical modulation functionality.
3Reliability
If grating coupler and MOS optical modulator are formed with stacked semiconductor layers, then light coupling efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by creating different structural features in different regions: gratings with specific duty cycles in the second semiconductor layer and rib waveguides with optimized dimensions in the first semiconductor layer. Each region is etched with parameters tailored to its specific function, allowing high light coupling efficiency while managing precision requirements through localized optimization rather than uniform high precision throughout.
Solution Approach 2:
The patent utilizes parameter changes by varying etching depth, width, and pattern geometry to achieve the desired grating and rib waveguide structures. By controlling etch depth to penetrate through the second semiconductor layer partially and forming ribs with specific height ratios, the patent achieves optimal light coupling efficiency while maintaining manufacturable precision levels through parameter optimization.
Data Source
AI summary
To reduce a production cost of a semiconductor device and provide a semiconductor device having improved characteristics. A grating coupler has a plurality of projections separated from each other in an optical waveguide direction and a slab portion formed between any two of the projections adjacent to each other and formed integrally with them; a MOS optical modulator has a projection extending in the optical waveguide direction and slab portions formed on both sides of the projection, respectively, and formed integrally therewith. The projection of the grating coupler and the MOS optical modulator is formed of a first semiconductor layer, a second insulating layer, and a second semiconductor layer stacked successively on a first insulating layer, while the grating coupler and the MOS optical modulator each have a slab portion formed of the first semiconductor layer.