VCSEL Emitter Layout With Short Oxidation Length and Segmented Trenches

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current vertical-cavity surface-emitting laser (VCSEL) designs face challenges in achieving a shorter oxidation length and a larger number of trenches without compromising performance or reliability, as they often result in carrier leakage due to fabrication limitations and design constraints.

Innovation Solution

The design includes an ohmic metallization layer with extended portions and tabs positioned outside the oxidation trenches, allowing for a shorter oxidation length and a larger number of trenches while maintaining carrier confinement and manufacturing tolerance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the oxidation length is reduced to increase emitter density, then the emitter density increases, but carrier leakage occurs compromising device reliability

Engineering Contradiction:

Improveemitter densityVSAvoidcarrier confinement

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The oxidation trenches are segmented into multiple discrete trenches arranged in a circular pattern around the emitter, rather than using a continuous oxidation barrier. This segmentation allows each trench to independently confine carriers while maintaining a shorter overall oxidation length, thus increasing emitter density without compromising carrier confinement reliability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from a radial oxidation approach to a circular array of discrete trenches, effectively changing the dimensional arrangement of the oxidation structures. This dimensional reconfiguration allows the oxidation length to be shortened while maintaining effective carrier confinement through the distributed trench structure

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If the number of oxidation trenches is increased to improve carrier confinement, then the carrier confinement improves, but the device complexity and fabrication difficulty increase

Engineering Contradiction:

Improvecarrier confinementVSAvoidtrench configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Multiple oxidation trenches are merged into a unified circular array configuration that functions as a single integrated carrier confinement structure. This merging approach maintains effective carrier confinement while simplifying the overall device design and reducing fabrication complexity compared to irregularly spaced or asymmetric trench arrangements

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent optimizes key parameters of the oxidation trenches including their radial position, angular spacing, and depth to achieve effective carrier confinement with a manageable number of trenches. By carefully controlling these parameters, the design achieves reliable carrier confinement without excessive device complexity or fabrication difficulty

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the oxidation trenches are positioned closer to the emitter to reduce oxidation length, then the emitter density increases, but manufacturing precision requirements increase due to fabrication limitations

Engineering Contradiction:

Improveemitter densityVSAvoidtrench positioning accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The oxidation trenches are positioned at specific radial distances from the emitter where they optimally balance carrier confinement effectiveness with manufacturing feasibility. This local optimization of trench position ensures that the trenches are close enough to the emitter to maintain short oxidation length and high emitter density, while being far enough to accommodate standard fabrication tolerances and achieve the required manufacturing precision

Inventive Principle:

Principle #3Local quality

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 enables increased emitter density and improved manufacturability without sacrificing performance or reliability, addressing the limitations of existing compact emitter designs.

Implementation Method 1

a plurality of oxidation trenches, wherein the plurality of extended portions of the p-ohmic metal layer extend outside outer radii of the plurality of oxidation trenches

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS11831129B2Vertical cavity surface emitting laser design with shorter oxidation length and/or larger number of trenches

Publication Date: 2023.11.28 WELLS FARGO BANK NA

AI summary

In some implementations, a surface emitting laser may have an emitter design with a short oxidation length and/or a large number of trenches. For example, the surface emitting laser may comprise a metallization layer comprising multiple extended portions extending outwards from a circumference of an inner ring portion, and multiple tabs extending laterally from the multiple extended portions in a partial ring shape. The surface emitting laser may further comprise multiple via openings connecting the metallization layer to a plating metal, where each via opening is positioned over a corresponding tab, of the multiple tabs. The surface emitting laser may comprise multiple oxidation trenches that are each formed in an angular gap between a pair of extended portions, of the multiple extended portions, such that the multiple tabs and the multiple via openings are exclusively outside outer radii of the multiple oxidation trenches.