Buried Guide Ribbon Structure for Dopant Diffusion Control

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Solution Overview

Problem

Ridge optoelectronic devices with semi-insulating buried heterostructures face issues of dopant diffusion and uncontrolled epitaxial overgrowth, leading to performance degradation and heating, particularly in misoriented components.

Innovation Solution

A method involving dielectric layers incompatible with epitaxy is used to confine the ribbon structure, preventing dopant diffusion and controlling epitaxial growth, ensuring proper alignment and insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a semi-insulating structure is used to confine the ribbon, then light confinement and electrical insulation are improved, but dopant inter-diffusion occurs causing performance degradation

Engineering Contradiction:
Improvelight confinement and electrical insulationVSAvoiddopant distribution control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

A dielectric layer is introduced as an intermediary barrier between the semi-insulating structure and the ribbon. This dielectric layer prevents direct contact and inter-diffusion of dopants (Fe from semi-insulating to P-doped layers) while maintaining the electrical insulation and light confinement functions of the semi-insulating structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The structure combines multiple materials with different properties: semi-insulating material for electrical insulation and light confinement, dielectric material for dopant barrier, and doped semiconductor layers for active functions. This composite approach allows each material to perform its optimal function without interfering with others.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If epitaxial growth is used to form the semi-insulating layer, then material quality is improved, but uncontrolled overgrowth occurs on misoriented ribbons

Engineering Contradiction:
Improvematerial qualityVSAvoidgrowth control
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The ribbon orientation is predetermined and controlled during the initial fabrication steps before epitaxial growth. By ensuring proper alignment of the ribbon with crystallographic directions prior to growth, the method prevents misorientation that would lead to uncontrolled overgrowth, while still allowing high-quality epitaxial growth to proceed.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If dopant diffusion is allowed during processing, then manufacturing simplicity is maintained, but leakage currents increase due to resistivity degradation

Engineering Contradiction:
Improveprocessing simplicityVSAvoidleakage current control
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The dielectric layer serves as a diffusion barrier that blocks the movement of dopant atoms between the semi-insulating structure and the ribbon during thermal processing. This prevents the degradation of resistivity in both structures and maintains low leakage currents while allowing standard processing temperatures and times.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Object-affected harmful factors

If the ribbon is buried in semi-insulating material, then parasitic capacitances are reduced, but Joule heating increases due to increased resistivity

Engineering Contradiction:
Improveparasitic capacitanceVSAvoidJoule heating
Core Design Contradiction:
Object-affected harmful factorsVSTemperature

Solution Approach 1:

The dielectric layer acts as a thermal management interface that prevents dopant contamination of the P-doped layers, thereby maintaining their low resistivity. This allows the buried ribbon structure to benefit from reduced parasitic capacitances while avoiding the Joule heating problem that would result from increased resistivity due to dopant diffusion.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 method enhances heat dissipation, reduces leakage currents, and maintains component performance by preventing dopant interdiffusion and overgrowth, allowing for aligned and misoriented components to be manufactured with improved efficiency.

Implementation Method 1

a first dielectric layer deposited on the first side face; a second dielectric layer deposited on the second side face... preventing dopant diffusion

Methodology Applied
Scientific EffectDiffusion barrier: Diffusion Barrier

Implementation Method 2

The semi-insulating material is generally a semiconductor material doped with a metal... allows better control of the spatial distribution of light and limits parasitic capacitances

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

the phenomenon of inter-diffusion of dopants in this case causes a degradation of the performance of the component... lack of control of the growth of the semiconductor layer by epitaxy

Methodology Applied
Scientific EffectEpitaxy: Epitaxy

Data Source

PatentEP4576457A1Optoelectronic component with ribbon embedded in a semi-insulating structure
Publication Date: 2025.06.25 THALES SA
  • EP4576457A1 patent drawingFigure 1a
  • EP4576457A1 patent drawingFigure 1b~1c
  • EP4576457A1 patent drawingFigure 2~3a

AI summary

The invention relates to an optoelectronic component comprising a stack of layers on a substrate in a stacking direction; said stack comprising: - a ribbon heterostructure comprising a base and a guide ribbon having a first lateral face and a second lateral face; - a first dielectric layer deposited on the first lateral face; - a second dielectric layer deposited on the second lateral face; - a semi-insulating structure in which the guide ribbon is buried; the first dielectric layer and the second dielectric layer each being confined between the semi-insulating layer and the guide ribbon.