Semiconductor Ridge Formation via Indicator Layer Etching

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Solution Overview

Problem

The challenge in manufacturing edge-emitting semiconductor laser diodes in ridge waveguide geometry lies in forming a uniform and reproducible ridge-shaped area due to inhomogeneities in semiconductor material composition and thickness, affecting operating parameters like laser threshold and mode behavior.

Innovation Solution

A method involving a semiconductor body with an active region and an indicator layer, where the indicator layer has a distinct material composition differing from the adjoining web-like area, allowing for precise adjustment of the web-like area's extent and distance from the active region during epitaxial deposition, and utilizing dry-chemical removal processes to form the ridge-like area with high reproducibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If etching process is used to form ridge-shaped area, then web-like area can be produced, but inhomogeneities in material composition and thickness lead to poor reproducibility

Engineering Contradiction:
Improveease of forming ridge-shaped areaVSAvoidreproducibility of web-like area dimensions
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The indicator layer is deposited beforehand during epitaxial growth at a predetermined position. This preliminary action establishes a reference marker that guides the subsequent etching process, ensuring that the web-like area is formed with precise and reproducible dimensions regardless of material inhomogeneities.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The indicator layer serves as an intermediary element between the epitaxial structure and the etching process. It provides a distinct material composition that enables precise detection of the etching front, allowing the etching process to stop at the correct position and form the web-like area with consistent dimensions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If indicator layer is used to control etching depth, then manufacturing precision improves, but device complexity increases

Engineering Contradiction:
Improveprecision of web-like area formationVSAvoidcomplexity of semiconductor layer sequence
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The indicator layer is integrated into the epitaxial growth process and serves multiple functions: it acts as a depth reference for etching, provides material composition contrast for detection, and maintains structural integrity during processing. This multi-functionality reduces the need for additional separate components or processes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The indicator layer utilizes changes in material composition parameters during epitaxial growth to create a detectable signature. By varying the composition within the indicator layer, a distinct signal is generated that enables precise control of etching depth without requiring complex external monitoring systems.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If web-like area dimensions are not uniform, then operating parameters fluctuate, but adjusting etching time to compensate increases process complexity

Engineering Contradiction:
Improvestability of operating parametersVSAvoidcomplexity of etching process control
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces time-based etching control with a material-composition-based control system. Instead of relying on precise timing and monitoring etching rates, the process uses the indicator layer's distinct material composition to automatically signal when the correct depth is reached, substituting mechanical process control with a material-based reference system.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 approach enables the formation of a web-like area with consistent dimensions, improving the reproducibility of semiconductor components, lowering the laser threshold, and enhancing the efficiency of charge carrier recombination within the active region.

Implementation Method 1

the semiconductor layer sequence is removed in regions by means of dry-chemical removal

Methodology Applied
Scientific EffectDry-chemical removal: Ablation

Implementation Method 2

a property of a process gas being monitored during the removal and reaching the indicator layer being determined by means of the change in the property of the process gas

Methodology Applied
Scientific EffectProperty monitoring of process gas:

Implementation Method 3

the indicator layer has a material composition that differs from that of the material of the web-like area adjoining the indicator layer

Methodology Applied
Scientific EffectMaterial composition differentiation:

Data Source

PatentEP2258029B1Method for producing a semiconductor component
Publication Date: 2018.11.07 OSRAM OPTO SEMICON GMBH & CO OHG
  • EP2258029B1 patent drawingFigure 1
  • EP2258029B1 patent drawingFigure 2~3
  • EP2258029B1 patent drawingFigure 4A~4B

AI summary

The invention relates to a semiconductor component with a semiconductor body (2) having a semiconductor layer sequence which has an active region (21) for the generation of coherent radiation and an indicator layer (3). On the side facing away from the active region of an interface (30) that delimits some sections of the semiconductor body (2) in the vertical direction, the semiconductor body (2) comprises a web-like region (4) which extends in the vertical direction between the interface (30) and a surface (40) of the semiconductor body (2). The indicator layer (3) has a material composition that differs from that of the material of the web-like region (4), which adjoins the indicator layer (3). The distance of the indicator layer (3) from the surface (40) is not greater than a distance of the interface (30) from the surface (40). The invention further relates to a method for producing a semiconductor component.