Nitride Semiconductor Laser Coating with Localized Argon Gradients

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Nitride semiconductor laser chips face reliability issues due to deterioration of resonator facets when operated at high optical output, as conventional protective coatings do not provide sufficient protection against light absorption, heating, and oxidation.

Innovation Solution

A nitride semiconductor laser chip with a coating film formed using a sputtering process, where the rare gas element content is varied between regions contiguous with and away from the resonator facets, with lower content near the facets to reduce light absorption and higher content on the surface to prevent moisture and oxygen diffusion, enhancing the catastrophic optical damage threshold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the rare gas element content is increased in the coating film to prevent moisture and oxygen diffusion, then the protection against oxidation is improved, but the light absorption and heating increase

Engineering Contradiction:

Improveprotection against oxidationVSAvoidheating from light absorption

Core Design Contradiction:

Object-affected harmful factorsVSTemperature

Solution Approach 1:

The coating film employs local quality variation with low rare gas content in the first region (near facet) to minimize light absorption and heating, while high rare gas content in the second region (away from facet) to maximize protection against oxidation. This spatial differentiation resolves the contradiction between oxidation protection and heating reduction.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The coating film is segmented into two functional regions: the first region optimized for reducing light absorption (lower rare gas content) and the second region optimized for preventing oxidation (higher rare gas content). This segmentation allows independent optimization of each function, resolving the contradiction.

Inventive Principle:

Principle #1Segmentation

2Temperature

If the rare gas element content is decreased in the coating film to reduce light absorption, then the heating is reduced, but the protection against moisture and oxygen diffusion is weakened

Engineering Contradiction:

Improveheating from light absorptionVSAvoidprotection against moisture and oxygen diffusion

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The coating film uses local quality variation where the first region has low rare gas content to reduce heating, while the second region has high rare gas content to provide strong protection against moisture and oxygen diffusion. This resolves the contradiction by assigning different compositions to different spatial locations.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The coating film is divided into two segments: the first segment (near facet) with low rare gas content for thermal management, and the second segment (away from facet) with high rare gas content for environmental protection. This segmentation enables simultaneous achievement of both goals.

Inventive Principle:

Principle #1Segmentation

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 structure effectively suppresses deterioration of the resonator facets by minimizing heating and oxidation, thereby ensuring sufficient reliability even at high optical output levels.

Implementation Method 1

a coating film formed on the resonator facet and containing a rare gas element... when a coating film is formed by a sputtering process using a rare gas element

Methodology Applied

Scientific EffectSputtering: Sputtering

Implementation Method 2

this makes it possible to suppress light absorption in the first region, and thus to suppress heating in the first region resulting from light absorption

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 3

the rare gas element content in the second region disposed on the side of the first region opposite from the resonator facet is made higher than in the first region; this makes it possible to form the coating film closely-packed in the second region. It is thus possible to suppress diffusion of moisture and oxygen from the atmosphere

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentUS8571083B2Nitride semiconductor laser chip

Publication Date: 2013.10.29 SHARP FUKUYAMA LASER CO LTD

AI summary

A nitride semiconductor laser chip is provided that offers sufficient reliability even at high output. The nitride semiconductor laser chip has a nitride semiconductor layer formed on a substrate, a resonator facet formed on the nitride semiconductor layer, and a coating film formed on the resonator facet and containing Ar. The coating film has, in a region contiguous with the resonator facet and in the vicinity thereof, a low-Ar region with a low Ar content and, on the side of this low-Ar region opposite from the resonator facet, a high-Ar region with a higher Ar content than the low-Ar region.