Semiconductor Ridge Structure for Stress Relief at Laser-Modulator Joints
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Solution Overview
Problem
Stress concentration at the joint part of semiconductor laser and optical modulator or waveguide integrated on a single substrate due to different ridge widths and etching depths, leading to reliability issues.
Innovation Solution
A semiconductor device with a substrate featuring a semiconductor laser part and an optical modulator or waveguide, where the ridge structures are designed with wider contact parts and varying conductivity types to alleviate stress concentration, achieved through a multilayer structure formation and etching process with a mask that ensures uniform composition and optimized ridge widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ridge width is changed to match different waveguide requirements, then optical performance is improved, but stress concentration occurs at the joint part
Solution Approach 1:
The patent applies local quality by making the ridge width non-uniform: the ridge is wider at the joint part and narrower at other parts. This local variation in geometry allows the joint region to have enhanced stress distribution properties while other regions maintain their optimal optical characteristics. The wider ridge at the joint specifically addresses the stress concentration problem without compromising the overall optical performance of the device.
Solution Approach 2:
The patent changes the geometric parameter of ridge width to resolve the stress concentration issue. By increasing the ridge width at the joint part, the structural parameter is modified to distribute stress more effectively. This parameter change transforms the uniform ridge structure into a non-uniform one that accounts for the specific mechanical requirements at the joint interface.
2Adaptability or versatility
If different etching depths are used for laser and modulator parts, then functional optimization is achieved, but steps form at the joint part causing stress concentration
Solution Approach 1:
The patent applies local quality by creating a wider ridge specifically at the joint part to compensate for the steps formed by different etching depths. This localized geometric modification ensures that the transition between laser and modulator parts is smoother mechanically, even though the etching depths remain different for functional optimization. The wider ridge acts as a stress-distributing feature at the critical joint interface.
3Ease of manufacture
If insulating film and metal are formed, then device functionality is completed, but stress accumulates at the joint part
Solution Approach 1:
The patent applies local quality by making the ridge wider at the joint part, creating a locally reinforced structure that can better accommodate the stress from subsequently formed insulating films and metal layers. This local geometric enhancement provides a mechanical foundation that reduces stress accumulation during the device fabrication process, while the rest of the structure maintains its original dimensions for optimal performance.
Data Source
AI summary
A semiconductor device includes a substrate, a semiconductor laser part formed on the substrate and having an active layer with an uniform composition and a first ridge structure, and an adjacent part formed on the substrate, having a core layer with an uniform composition and a second ridge structure, and being an optical modulator or an optical waveguide which is in contact with the semiconductor laser part, wherein the first ridge structure is largest in width at a first contact part which is in contact with the second ridge structure, and the second ridge structure is largest in width at a second contact part which is in contact with the first ridge structure.