VCSEL Cavity Growth Using MOCVD and MBE Layer Segmentation

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Solution Overview

Problem

Conventional laser devices face challenges in forming high-quality layers and structures due to the limitations of single deposition processes, which can lead to defects and degrade performance, manufacturability, and reliability.

Innovation Solution

A multiphase growth sequence is employed, utilizing a combination of Metal-Organic Chemical Vapor Deposition (MOCVD) and Molecular Beam Epitaxy (MBE) processes to form different layers of a VCSEL device, allowing for the creation of high-quality mirrors, tunnel junctions, and active regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a single deposition process (MOCVD or MBE) is used to form all layers, then the manufacturing process is simple, but the quality of layers and structures deteriorates with defects and performance degradation

Engineering Contradiction:

Improvequality of layers and structuresVSAvoidcomplexity of deposition process

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The deposition process is segmented into two distinct phases: MOCVD phase for forming first mirror, tunnel junction, OA layer, and p-doped layer; and MBE phase for forming active region, second mirror, and contact layer. This segmentation allows each process to optimize for specific layer requirements, achieving high manufacturing precision without requiring a single complex process to handle all layers

Inventive Principle:

Principle #1Segmentation

2Reliability

If a single deposition process is used, then the manufacturing process is easy to implement, but reliability of the VCSEL device deteriorates due to defects

Engineering Contradiction:

Improvereliability of VCSEL deviceVSAvoidease of deposition process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Different deposition processes are applied to different regions/layers based on their specific quality requirements. MOCVD is used for layers requiring high crystalline quality (first mirror, tunnel junction), while MBE is used for layers requiring precise compositional control (active region, second mirror). This local quality approach ensures each layer achieves the reliability needed for its function

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If MOCVD process is used for all layers, then the manufacturing process is simple, but the performance of the VCSEL device deteriorates due to inability to form high-quality active region

Engineering Contradiction:

Improvequality of active regionVSAvoidcomplexity of growth sequence

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The MOCVD process is performed first to prepare the foundational layers (first mirror, tunnel junction, OA layer, p-doped layer) that provide the structural and electrical framework. Then the MBE process is applied to form the high-performance active region and second mirror on top of this prepared structure, achieving high manufacturing precision for the critical active region

Inventive Principle:

Principle #10Preliminary action

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 enhances the quality of layers and structures within the VCSEL device, reducing the likelihood of defects and improving the device's performance, manufacturability, and reliability compared to single-process deposition methods.

Implementation Method 1

the first mirror, the tunnel junction, the OA layer, and the p-doped layer are formed using a metal-organic chemical vapor deposition (MOCVD) process

Methodology Applied

Scientific EffectChemical Vapor Deposition: Chemical Vapour Deposition

Implementation Method 2

the active region, the second mirror, and the contact layer are formed using a molecular beam epitaxy (MBE) process

Methodology Applied

Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Data Source

PatentUS12334713B2Methods for forming a vertical cavity surface emitting laser device

Publication Date: 2025.06.17 WELLS FARGO BANK NA

AI summary

A method of forming a VCSEL device cavity using a multiphase growth sequence includes forming a first mirror over a substrate, forming a tunnel junction over the first mirror, forming an oxidation aperture (OA) layer over the tunnel junction, forming a p-doped layer over the OA layer, forming an active region over the p-doped layer, forming a second mirror over the active region, and forming a contact layer over the second mirror. The first mirror, the tunnel junction, the OA layer, and the p-doped layer are formed using a metal-organic chemical vapor deposition (MOCVD) process during an MOCVD phase of the multiphase growth sequence. The active region, the second mirror, and the contact layer are formed using a molecular beam epitaxy (MBE) process during an MBE phase of the multiphase growth sequence.