Ridge Laser Diode Cladding Layout to Prevent Peeling and Leakage

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Solution Overview

Problem

Conventional GaN-based laser diodes suffer from poor adhesion of the cladding layer with the p-type semiconductor layer, leading to peeling or damage, which results in electrical leakage and inadequate light field confinement, affecting performance.

Innovation Solution

The laser diode design includes an optical cladding layer with a first portion covering the side walls and a second portion as island structures on the top surface of the ridge structure, made of materials with lower refractive index than the electrode contacting layer, enhancing adhesion and light confinement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional optical cladding layer is used to cover the ridge structure, then light field confinement is provided, but the cladding layer has poor adhesion with the p-type semiconductor layer causing peeling or damage

Engineering Contradiction:

Improveadhesion of cladding layerVSAvoidpeeling or damage of cladding layer

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The optical cladding layer is segmented into a first cladding portion covering side walls and a second cladding portion as island structures on the top surface. This segmentation allows the cladding layer to adhere better to the ridge structure by distributing the adhesion points, preventing peeling while maintaining light confinement functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cladding layer is applied differently in different locations: continuously on side walls and as discrete island structures on the top surface. This local quality variation optimizes adhesion in critical areas while maintaining optical confinement, preventing peeling in regions where it matters most.

Inventive Principle:

Principle #3Local quality

2Reliability

If the metal layer entirely covers the top surface of the ridge structure, then electrical connection is achieved, but the light field distribution becomes unbalanced

Engineering Contradiction:

Improveelectrical connectionVSAvoidlight field distribution

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The metal layer is configured with different coverage in different regions: it provides complete electrical connection where needed while leaving portions of the top surface exposed. This local differentiation allows simultaneous achievement of reliable electrical connection and balanced light field distribution by controlling where metal covers and where light can interact with the semiconductor surface.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If the cladding layer is damaged or peeled, then manufacturing simplicity is maintained, but electrical leakage occurs and light field confinement is insufficient

Engineering Contradiction:

Improvecladding layer formationVSAvoidelectrical leakage prevention

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

By segmenting the cladding layer into side wall coverage and top surface island structures, the design creates multiple independent adhesion zones. This segmentation ensures that even if one area experiences stress, the overall cladding integrity is maintained through other adhesion points, preventing electrical leakage while keeping the manufacturing process simple.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The segmented cladding structure provides built-in redundancy that cushions against potential failure. By creating multiple adhesion pathways before any damage can occur, the design preemptively protects against peeling and electrical leakage, ensuring reliability without complicating manufacturing.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 design reduces the risk of electrical leakage, improves current diffusion, and balances light field distribution, resulting in enhanced light output efficiency and extended service life.

Implementation Method 1

The optical cladding layer has a refractive index smaller than that of the electrode contacting layer. The optical cladding layer includes a first cladding portion which covers side walls of the ridge structure, and a second cladding portion which is disposed on a portion of the top surface of the ridge structure.

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

The p-type semiconductor layer is formed with a ridge structure 31 by inductively coupled plasma (ICP) etching.

Methodology Applied

Scientific EffectPlasma etching: Plasma

Data Source

PatentUS12506324B2Laser diode and method for manufacturing the same

Publication Date: 2025.12.23 QUANZHOU SANAN SEMICON TECH CO LTD

AI summary

A laser diode includes a substrate, an epitaxial structure, an electrode contacting layer and an optical cladding layer. The epitaxial structure is disposed on the substrate, and is formed with a ridge structure opposite to the substrate. The electrode contacting layer is disposed on a top surface of the ridge structure. The optical cladding layer has a refractive index smaller than that of the electrode contacting layer. The optical cladding layer includes a first cladding portion which covers side walls of the ridge structure, and a second cladding portion which is disposed on a portion of the top surface of the ridge structure. A method for manufacturing the abovementioned laser diode is also disclosed.