Semiconductor Laser Ridge Spacers for Junction-Down Bonding
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Solution Overview
Problem
Junction-down bonding of semiconductor laser elements often results in inclination due to the protruded shape of the ridge, which affects heat dissipation and bonding stability.
Innovation Solution
The semiconductor laser element incorporates spacers on either side of the ridge, spaced apart from the ridge, to prevent inclination during bonding and enhance heat dissipation by allowing the pad electrode to be mounted on both the ridge and the spacer, thereby distributing heat effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If junction-down bonding is performed on a ridge-type semiconductor laser element, then heat dissipation is improved, but inclination occurs during bonding due to the protruded ridge shape
Solution Approach 1:
The patent introduces a spacer as an intermediary component between the ridge and the bonding interface. This spacer acts as a mediator that compensates for the height difference caused by the protruded ridge, enabling stable planar bonding while preserving the heat dissipation benefits of junction-down configuration. The spacer material and dimensions are specifically designed to fill the gap created by the ridge protrusion.
Solution Approach 2:
The patent applies local quality by providing the spacer only in specific locations where needed - namely, at the bonding interface areas adjacent to the ridge, rather than uniformly across the entire device. This localized approach prevents inclination at the bonding interface while maintaining the ridge's heat dissipation function and avoiding unnecessary complexity in non-critical areas.
2Temperature
If the ridge structure is used for mounting, then heat dissipation is enhanced, but teetering occurs centering on the ridge causing inclination
Solution Approach 1:
The spacer functions as a counterweight structure that compensates for the uneven height distribution caused by the protruded ridge. By providing additional height at the bonding interface through the spacer, the system achieves balance and prevents teetering during mounting, thereby improving reliability without sacrificing the ridge's heat dissipation capability.
3Stability of the object's composition
If a spacer is provided to prevent inclination, then bonding stability is improved, but heat dissipation may be deteriorated if the spacer covers entire surfaces
Solution Approach 1:
The patent implements local quality by restricting the spacer to specific locations - primarily at the bonding interface areas adjacent to the ridge - rather than covering the entire device surface. This localized placement ensures bonding stability is achieved where needed while minimizing the spacer's impact on heat dissipation pathways, as the spacer does not blanket the entire heat-generating and heat-dissipating surfaces.
Solution Approach 2:
The patent applies partial action by providing the spacer only to the extent necessary for preventing inclination - specifically at the bonding interface regions - rather than applying it excessively across all surfaces. This partial coverage is sufficient to achieve the bonding stability goal while avoiding the heat dissipation deterioration that would result from complete surface coverage.
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 prevents teetering and improves heat dissipation by ensuring stable bonding and efficient thermal conductivity, as demonstrated by comparative thermal resistance, current-optical output, and life characteristics measurements.
Implementation Method 1
a spacer 5a, 5b, 5c which is/are disposed on a part of the insulating layer 4, and on which the pad electrode 6 is disposed
Implementation Method 2
heat dissipation will not to be deteriorated as in the case where the spacer is disposed on approximately entire surfaces of the spacer on the both sides of the ridge
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
To provide a ridge-type semiconductor laser element capable of preventing inclination at the time of junction-down bonding and having high heat dissipation, in a semiconductor laser element including a substrate, a semiconductor portion disposed on the substrate and having a ridge on a surface at an opposite side from the substrate, an electrode disposed on a ridge, an insulating layer disposed on the semiconductor portion at the both sides of the ridge and a pad electrode disposed on the electrode, in which, the pad electrode side is a mounting surface side, the pad electrode is disposed extending on the insulating layer, and a spacer is disposed between the semiconductor portion and the pad electrode at parts spaced apart from the ridge.