Semiconductor Optical Waveguide Electrode Layout for Thermal Stability

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Solution Overview

Problem

Semiconductor optical devices experience thermal deformation due to differences in thermal expansion coefficients between semiconductor and metal layers, leading to increased electrical resistance and reduced thermal dissipation, especially in devices with multiple waveguides, which complicates optical coupling efficiency.

Innovation Solution

The semiconductor optical device incorporates electrodes with varying thicknesses, including a thinner first portion and a thicker second portion, aligned to minimize thermal deformation and maintain electrical conductivity and thermal dissipation, while optimizing the relative positions of waveguides.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the volume of the metal layer is reduced to hold down thermal deformation, then thermal deformation is reduced, but the electrical resistance increases and thermal dissipation declines

Engineering Contradiction:

Improvethermal deformationVSAvoidelectrical resistance

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The electrode is designed with non-uniform thickness, having a first portion and a second portion with different thicknesses. The thinner first portion reduces thermal deformation in critical areas, while the thicker second portion maintains adequate electrical conductivity and thermal dissipation where needed. This local variation in thickness allows simultaneous optimization of thermal stability and electrical performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The electrode is segmented into multiple portions with different thicknesses rather than using a uniform thickness throughout. This segmentation allows different regions of the electrode to serve different functions: the thinner first portion minimizes thermal deformation, while the thicker second portion ensures sufficient electrical conductivity and heat dissipation capacity.

Inventive Principle:

Principle #1Segmentation

2Stability of the object's composition

If the volume of the metal layer is reduced to hold down thermal deformation, then thermal deformation is reduced, but thermal dissipation undergoes a decline

Engineering Contradiction:

Improvethermal deformationVSAvoidthermal dissipation

Core Design Contradiction:

Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The electrode thickness is optimized locally rather than uniformly. The thinner first portion is positioned where thermal deformation control is most critical, while the thicker second portion is positioned where thermal dissipation is most needed. This local differentiation allows the electrode to simultaneously minimize thermal deformation and maintain adequate thermal dissipation performance.

Inventive Principle:

Principle #3Local quality

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

This configuration effectively reduces thermal deformation, maintains electrical conductivity, and enhances optical coupling efficiency by stabilizing the relative positions of waveguides, thereby improving the overall performance of the semiconductor optical device.

Implementation Method 1

if there is a significant temperature difference between the time of manufacturing and at the time of operation, due to the difference in the coefficient of thermal expansion of the semiconductor layer and the coefficient of thermal expansion of the metal layer, there occurs a difference in the extent of heat contraction depending on the position

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

there occurs a difference in the extent of heat contraction depending on the position

Methodology Applied

Scientific EffectThermal contraction: Thermal Contraction

Implementation Method 3

a plurality of waveguide structures each of which includes a first cladding layer, a core layer, and a second cladding layer that are layered in the first direction, the plurality of waveguide structures extending in a second direction that intersects with the first direction and guiding lights in the second direction

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS20250357725A1Semiconductor optical device and optical integrated device

Publication Date: 2025.11.20 FURUKAWA ELECTRIC CO LTD

AI summary

A semiconductor optical device includes: a substrate expanding while intersecting with a first direction; a plurality of waveguide structures each of which includes a first cladding layer, a core layer, and a second cladding layer that are layered in the first direction, the plurality of waveguide structures extending in a second direction that intersects with the first direction and guiding lights in the second direction or opposite direction to the second direction, and being disposed away from each other in a third direction that intersects with the first direction and the second direction; and a first electrode disposed on an opposite side of the substrate with respect to the waveguide structures, and including a first portion and a second portion having a thickness thicker than a thickness of the first portion in the first direction.