Optoelectronic Semiconductor Chip Flank Passivation

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Solution Overview

Problem

Existing optoelectronic semiconductor chips face inefficiencies due to high radiation absorption at the flanks, leading to significant radiation losses, which reduces their overall efficiency.

Innovation Solution

The implementation of a second passivation layer with a lower refractive index than the first passivation layer, strategically placed between the first passivation layer and the semiconductor body, reduces total internal reflection and absorption, thereby minimizing radiation losses and enhancing efficiency. This layer is designed to cover the flanks and is typically formed from materials like silicon dioxide, ensuring transparency and reduced absorption of emitted radiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a first passivation layer is applied to the flanks of the semiconductor body, then the semiconductor body is protected and structured, but radiation absorption at the flanks increases significantly

Engineering Contradiction:

Improveprotection of semiconductor bodyVSAvoidradiation absorption at flanks

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

A second passivation layer with lower refractive index is introduced as an intermediary between the semiconductor body and the first passivation layer. This intermediate layer mediates the optical interaction by reducing the refractive index contrast at the interface, thereby minimizing total internal reflection and reducing radiation absorption at the flanks from 5% to 2%.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The refractive index parameter of the passivation system is changed by introducing a second passivation layer with a lower refractive index than the first passivation layer. This parameter change optimizes the optical properties at the flank interfaces, reducing radiation losses while maintaining the protective function.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If the flanks are covered with passivation material, then the semiconductor structure is stabilized, but total internal reflection increases causing radiation losses

Engineering Contradiction:

Improvestructural stability of flanksVSAvoidradiation losses due to total internal reflection

Core Design Contradiction:

Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The second passivation layer acts as an optical intermediary that reduces the refractive index mismatch between the semiconductor body and the first passivation layer. This intermediary layer decreases total internal reflection at the interfaces while the first passivation layer continues to provide structural stabilization to the flanks.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

A composite passivation structure is created using two different passivation materials with different refractive indices. The first passivation layer provides structural stability and protection, while the second passivation layer with lower refractive index optimizes optical properties by reducing total internal reflection, together forming a functionally optimized composite system.

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

The solution effectively reduces radiation absorption at the flanks from 5% to 2%, thereby increasing the semiconductor chip's efficiency by up to 3% and improving overall performance by minimizing direct losses and reflections.

Implementation Method 1

reduces total internal reflection and absorption, thereby minimizing radiation losses

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

The refractive index for the radiation of the second passivation layer generated by the active layer during operation is smaller than the refractive index of the first passivation layer

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS20220336713A1Optoelectronic semiconductor chip and method for producing thereof

Publication Date: 2022.10.20 OSRAM OPTO SEMICON GMBH & CO OHG

AI summary

An optoelectronic semiconductor chip may include a semiconductor body having an upper side and flanks running transversely to the upper side which delimit the semiconductor body in a lateral direction. The flanks are each covered with a first passivation layer. In the region of the flanks in each case a second passivation layer may be arranged between the first passivation layer and the semiconductor body, the index of refraction of the second passivation layer being lower than the index of refraction of the first passivation layer. The indices of refraction may be understood to be the indices of refraction for the radiation generated by the active layer during operation.