Buried Ridge Optoelectronic Structure With Nitride Heat Insulation

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Solution Overview

Problem

Current buried ridge structures in optoelectronic devices face inadequate heat dissipation and electrical insulation issues, particularly in high-power applications, leading to performance degradation and potential device damage.

Innovation Solution

A heterostructure with a crest embedded in a nitride coating, specifically aluminum nitride or boron nitride, which provides improved thermal conductivity and electrical insulation, combined with a manufacturing process that avoids aggressive etching to protect the structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a benzocyclobutene (BCB) coating is used for the buried ridge structure, then electrical insulation is improved, but heat dissipation deteriorates due to low thermal conductivity

Engineering Contradiction:
Improveelectrical insulationVSAvoidheat dissipation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent employs a composite coating structure consisting of multiple layers with different materials and functions. The first coating layer (BCB or similar polymer) provides electrical insulation, while the second coating layer (metal nitride such as AlN, SiN, or BN) provides high thermal conductivity for heat dissipation. This composite approach allows simultaneous achievement of both electrical insulation and effective heat dissipation, resolving the contradiction between these two requirements.

Inventive Principle:
Principle #40Composite materials

2Temperature

If a metal-doped semiconductor coating layer is used, then heat dissipation is improved, but electrical insulation deteriorates leading to increased loss currents and parasitic capacitances

Engineering Contradiction:
Improveheat dissipationVSAvoidelectrical insulation
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent employs a composite coating structure consisting of multiple layers with different materials and functions. The first coating layer (BCB or similar polymer) provides electrical insulation, while the second coating layer (metal nitride such as AlN, SiN, or BN) provides high thermal conductivity for heat dissipation. This composite approach allows simultaneous achievement of both electrical insulation and effective heat dissipation, resolving the contradiction between these two requirements.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If aggressive etching solutions are used to manufacture the buried ridge structure, then manufacturing precision is improved, but device reliability deteriorates due to potential damage to the crested heterostructure

Engineering Contradiction:
Improveridge structure fabricationVSAvoiddevice integrity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent introduces a sacrificial layer (such as SiO2, Si3N4, or organic polymer) as an intermediary material during the fabrication process. This sacrificial layer is deposited over the ridge structure before the nitride coating layer. The sacrificial layer can be selectively removed through localized etching without damaging the underlying ridge structure, as it serves as a protective intermediary. This approach enables precise manufacturing while preserving device integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies the nitride coating layer over the ridge structure before performing the localized etching to create the buried ridge configuration. This preliminary coating action protects the ridge structure from damage during subsequent etching operations. The nitride layer serves as a protective barrier that can withstand the etching process, allowing precise fabrication while maintaining device integrity.

Inventive Principle:
Principle #10Preliminary action

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 solution enhances heat dissipation and electrical insulation, enabling high-frequency and high-power operation while maintaining device stability and reliability, and allows for flip-chip assembly.

Implementation Method 1

a nitride coating layer, in which said guide ribbon is buried... offers considerable advantages in terms of performance improvement, heat dissipation

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a nitride coating layer, in which said guide ribbon is buried... offers considerable advantages in terms of performance improvement, heat dissipation, and electrical insulation

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Data Source

PatentEP4481961B1Optoelectronic component with a high-power buried ridge
Publication Date: 2026.02.11 THALES SA
  • EP4481961B1 patent drawingFigure 1
  • EP4481961B1 patent drawingFigure 2~3a
  • EP4481961B1 patent drawingFigure 3b~3c

AI summary

The invention relates to an optoelectronic component comprising a stacking of layers on a substrate along a stacking direction; said stacking comprising: - a crest heterostructure comprising a base and a guide ribbon extending along a guide direction orthogonal to the stacking direction, the guide ribbon being configured to propagate a confined light wave; - a nitride coating layer, in which said guide ribbon is buried.