Nitride Semiconductor Laser Chip Notched Substrate Thermal Pathway

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Solution Overview

Problem

Conventional heat dissipation methods for nitride semiconductor laser elements, such as connecting wires to the p-side electrode, are insufficient in improving heat dissipation performance, leading to reduced element lifespan and reliability, especially in high-power applications where heat generation is substantial.

Innovation Solution

A semiconductor laser chip design featuring notched portions on the substrate with a second metal layer in contact with the first metal layer, allowing for enhanced heat dissipation by embedding the chip in a heat dissipating material like solder, thereby reducing the distance from the optical waveguide to the heat dissipating material and improving thermal contact area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional heat dissipation methods (connecting wires to p-side electrode) are used, then device structure is simple, but heat dissipation performance is insufficient

Engineering Contradiction:

Improvedevice structure simplicityVSAvoidheat dissipation performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent transitions from planar heat dissipation (wires on surface) to three-dimensional heat dissipation by forming notched portions that extend vertically into the substrate. This allows heat dissipation material to contact the chip at multiple depth levels, significantly improving thermal coupling without complicating the overall device structure.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The notched portions create nested structures where the heat dissipation material embeds into the substrate notches, forming a hierarchical thermal pathway. The metal layer is nested within the notched regions, and the heat dissipation material further nests around these structures, creating efficient thermal conduction paths at multiple scales.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Duration of action of moving object

If ridge width is increased to reduce optical density, then element lifespan should improve, but heat dissipation remains insufficient

Engineering Contradiction:

Improveelement lifespanVSAvoidheat dissipation

Core Design Contradiction:

Duration of action of moving objectVSTemperature

Solution Approach 1:

The substrate is segmented by forming multiple notched portions that divide the heat dissipation function into discrete vertical channels. These notches create separate thermal pathways that collectively improve overall heat dissipation capacity, allowing the broad area structure to maintain both low optical density and effective thermal management.

Inventive Principle:

Principle #1Segmentation

3Reliability

If more wires are connected to p-side electrode, then heat dissipation area increases, but manufacturing complexity increases

Engineering Contradiction:

Improveheat dissipation areaVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the electrical connection function (metal layer) with the heat dissipation function (notched portions) into a single integrated structure. The metal layer serves both as an electrical contact and as a thermal conduction path, eliminating the need for separate wire connections and reducing manufacturing complexity while increasing effective heat dissipation area.

Inventive Principle:

Principle #5Merging (Combining)

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 design effectively prolongs the lifespan of the semiconductor laser chip by improving heat dissipation performance, reducing the deterioration of the optical waveguide, and enhancing the reliability of the nitride semiconductor laser device.

Implementation Method 1

first notched portions (5) formed in regions including a substrate (10) and running along an optical waveguide (20), wherein notched surfaces (5a) of the first notched portions (5) are covered with a second metal layer (24), which is in contact with a first metal layer (23)

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS8861561B2Semiconductor laser chip, semiconductor laser device, and semiconductor laser chip manufacturing method

Publication Date: 2014.10.14 SHARP FUKUYAMA LASER CO LTD

AI summary

Provided is a semiconductor laser chip improved more in heat dissipation performance. This semiconductor laser chip includes a substrate, which has a front surface and a rear surface, nitride semiconductor layers, which are formed on the front surface of the substrate, an optical waveguide (ridge portion), which is formed in the nitride semiconductor layers, an n-side electrode, which is formed on the rear surface of the substrate, and notched portions, which are formed in regions that include the substrate to run along the optical waveguide (ridge portion). The notched portions have notched surfaces on which a metal layer connected to the n-side electrode is formed.