Quantum Cascade Laser Base with Integrated Thermal and Electrical Contacts
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Solution Overview
Problem
Existing quantum cascade lasers with undoped, electrically insulating substrates face challenges in thermal dissipation and electrical connection, leading to complex mounting processes and potential wire failure during cooling cycles, especially when trying to mount them epitaxially face down without gold wires.
Innovation Solution
A thermally conductive and electrically insulating matrix is structured to match the shape of the laser waveguide and substrate, allowing direct contact for both electrical powering and heat dissipation, eliminating the need for gold wires and simplifying the mounting process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the laser is mounted epitaxially face down with a thermally conductive base, then heat dissipation is improved, but electrical connection becomes complex requiring gold wires and additional lithography steps
Solution Approach 1:
The patent combines the thermal management function and electrical connection function into a single integrated base structure. The base simultaneously provides thermally conductive pathways for heat dissipation and electrically conductive pathways for power delivery, eliminating the need for separate gold wire connections and reducing manufacturing complexity.
Solution Approach 2:
The base is designed to perform multiple functions: it serves as both a thermal management component (dissipating heat from the laser) and an electrical connection component (providing power to the laser through integrated conductive pathways). This multi-functional design eliminates the need for separate components and simplifies the overall assembly.
2Reliability
If gold wires are used for electrical connection in epitaxial-face-down mounting, then electrical powering is achieved, but the wires may detach during cooling cycles or melt if current is too high
Solution Approach 1:
The patent extracts and eliminates the fragile gold wire component from the system by integrating electrical conduction directly into the base structure. This removes the reliability issues associated with wire attachment and melting, as the electrical connection is now part of the solid, integrated base rather than a separate, vulnerable component.
Solution Approach 2:
The base acts as an intermediary structure that simultaneously manages thermal and electrical pathways. By using materials with appropriate thermal and electrical conductivity properties, the base provides stable, robust connections that eliminate the need for fragile wire intermediaries while maintaining reliable power delivery and heat dissipation.
3Ease of manufacture
If the insulating substrate has low thermal conductivity, then electrical insulation is maintained, but heat diffusion in the semiconductor waveguide is poor
Solution Approach 1:
The patent segments the thermal management function from the electrical insulation function by introducing a separate base structure. The insulating substrate maintains its electrical insulation properties, while the additional thermally conductive base provides the necessary heat diffusion pathway without compromising the electrical insulation of the original substrate.
Solution Approach 2:
The overall assembly uses composite material strategy: the insulating substrate provides electrical insulation, while the thermally conductive base provides heat dissipation. This composite structure allows both electrical insulation and effective heat diffusion to coexist by using different materials optimized for their respective functions in different parts of the assembly.
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 solution enhances heat dissipation, lowering the internal laser temperature by several tens of Kelvin and significantly increasing optical power performance, as confirmed by thermal simulations.
Implementation Method 1
a thermally conductive and electrically insulating matrix, structured so as to conform to the shape of the laser waveguide and the shape of the insulating substrate so that the semiconductor waveguide is in contact with the matrix, which is itself in contact with a cold thermal reservoir
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The present invention relates to an assembly which comprises a quantum cascade laser (1), and an associated base (2) including a thermally conductive and electrically insulated matrix (21) structured so as to match the shape of the laser waveguide and the shape of the insulating substrate (11) so that: the upper electrical contact (13) of the laser is in contact with the central electrical contact (23) of the base over the length of the matrix, and the lateral electrical contact (14, 15) of the laser is in contact with the lateral electrical contact (24, 25) of the base.