Optoelectronic Semiconductor Chip Reflective Layer Sequence

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Solution Overview

Problem

Optoelectronic semiconductor chips face efficiency losses due to low reflectivity of contact metallization, which absorbs reflected electromagnetic radiation, leading to photon recycling and reduced performance in optical systems.

Innovation Solution

The integration of a first reflective layer sequence with higher reflectivity than the contact metallization, applied to the surface away from the radiation passage area, and a second reflective layer sequence on the current distribution metallization, both comprising metals and dielectric layers to enhance reflectivity and prevent radiation absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If contact metallization is applied to the radiation passage area for electrical contact, then electrical functionality is achieved, but reflectivity decreases and radiation is absorbed

Engineering Contradiction:
Improveelectrical contact functionalityVSAvoidradiation absorption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies a composite structure consisting of contact metallization combined with a reflective layer sequence. The contact metallization (e.g., gold, aluminum, or copper) provides electrical conductivity, while the reflective layer sequence (comprising dielectric layers with different refractive indices) provides high reflectivity. This composite structure allows the contact area to simultaneously achieve both electrical functionality and optical reflectivity, preventing energy loss while maintaining electrical contact capability.

Inventive Principle:
Principle #40Composite materials

2Loss of energy

If reflective layer sequence is applied to contact metallization to increase reflectivity, then radiation reflection is improved, but device complexity increases

Engineering Contradiction:
Improveradiation reflection efficiencyVSAvoidlayer structure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent optimizes the reflective layer sequence by carefully selecting and controlling the optical parameters of dielectric layers, specifically their refractive indices and thicknesses. By adjusting these parameters, the system achieves high reflectivity (above 90%) in the target wavelength range while keeping the layer sequence compact and manufacturable. This parameter optimization allows achieving high performance without excessive structural complexity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent transitions from considering only the electrical contact function to adding the optical reflection dimension. By designing the contact area as a multi-layer structure that addresses both electrical and optical requirements simultaneously, the solution resolves the contradiction between improved reflection and increased complexity through integrated design.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If current distribution metallization is applied to the radiation passage area for uniform current distribution, then current distribution is improved, but reflectivity decreases and radiation is absorbed

Engineering Contradiction:
Improvecurrent distribution uniformityVSAvoidradiation absorption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies the same composite material principle to current distribution metallization. The current distribution layer (providing uniform current distribution across the radiation passage area) is combined with a reflective layer sequence. This composite structure enables the current distribution tracks to maintain their electrical function while achieving high optical reflectivity, preventing radiation absorption by the metallization.

Inventive Principle:
Principle #40Composite materials

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 significantly increases the reflectivity of the contact and current distribution tracks, preventing radiation loss and improving the efficiency of optoelectronic components by reflecting electromagnetic radiation back into the optical system, thereby enhancing the overall performance of optoelectronic semiconductor chips and components.

Implementation Method 1

a first reflective layer sequence (2b) which is applied to that surface of the contact metallization (2a) which is remote from the radiation passage area (3), the first reflective layer sequence being provided for reflecting electromagnetic radiation reflected back to the contact metallization

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2160773B1Optoelectronic semiconductor chip
Publication Date: 2018.11.07 OSRAM OPTO SEMICON GMBH & CO OHG
  • EP2160773B1 patent drawingFigure 1A~1C
  • EP2160773B1 patent drawingFigure 2A~2C
  • EP2160773B1 patent drawingFigure 3~4

AI summary

Disclosed is an optoelectronic semiconductor chip (1) comprising a radiation-permeable surface (3), a metallic contact coating (2a) that is applied to the radiation-permeable surface (3), and a first series of reflecting layers (2b) which is applied to the surface of the metallic contact coating (2a) facing away from the radiation-permeable surface (3). Also disclosed is an optoelectronic component comprising such a chip.