Multi-Terraced Electrode Structure for Optical Waveguide Stress Relief
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Solution Overview
Problem
The existing semiconductor optical devices face reliability issues due to stress caused by differences in thermal expansion coefficients between the electrode and semiconductor multilayers, which can deteriorate the device's performance.
Innovation Solution
A semiconductor optical device with a multi-layered and multi-terraced electrode structure is proposed, where the electrode has an uppermost Au layer, a lowermost layer with higher adhesion to the semiconductor multilayers, and includes stress relief layers with a Young's modulus equal to or lower than Au, dispersed across three or more sections with varying thicknesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-layered electrode structure with Au layer is used, then electrical and thermal continuity is improved, but stress in semiconductor multilayers increases due to thermal expansion coefficient differences
Solution Approach 1:
The electrode structure is segmented into multiple sections along the optical waveguide direction, with each section having different thickness configurations. This segmentation allows stress to be distributed and managed locally in different regions, preventing uniform stress accumulation across the entire semiconductor multilayer structure.
Solution Approach 2:
Different sections of the electrode are designed with different thicknesses and layer compositions tailored to local requirements. Sections closer to the end face have different characteristics than those farther away, allowing optimization of both stress management and electrical/thermal continuity in different regions.
2Stress or pressure
If a multi-terraced structure with varying thicknesses is implemented, then stress dispersion is improved, but device complexity increases
Solution Approach 1:
The multi-terraced structure segments the electrode into discrete sections with varying thicknesses, creating a stepped profile that disperses stress through geometric variation. This segmentation achieves stress management while maintaining a manufacturable structure using standard deposition and etching processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The multi-terraced electrode structure effectively disperses stress in the semiconductor multilayers, reduces the impact of thermal expansion differences, and enhances the device's reliability and heat dissipation capabilities.
Implementation Method 1
a second section adjacent to the first section, including the lowermost layer and additionally a stress relief layer comprising a material equal to or lower than Au in Young's modulus
Implementation Method 2
there are differences in thermal expansion coefficient between the electrode and the semiconductor multilayers, so a stress may occur in the semiconductor multilayers
Implementation Method 3
an uppermost layer is intended for providing electrical and thermal continuity from outside
Data Source
AI summary
A multi-terraced structure includes three or more sections with different thicknesses and adjacent to each other in a direction in which an optical waveguide extends. An adjacent pair of the three or more sections includes one section smaller in thickness and closer to an end face of the semiconductor multilayers and another section larger in thickness and farther from the end face of the semiconductor multilayers. The three or more sections include: a first section with a smallest thickness, including the lowermost layer; a second section adjacent to the first section, including the lowermost layer and additionally a stress relief layer composed of a material equal to or lower than Au in Young's modulus; and a third section with a largest thickness, including all layers from the uppermost layer to the lowermost layer.