Quantum Cascade Laser Insulating Portion Prevents Breakdown
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Solution Overview
Problem
The existing quantum cascade lasers face issues with breakdown and short circuits at the rear end face due to high voltage application, leading to device failure and reduced productivity, primarily because of the thin insulating film between the metal film and the electrode, which is prone to breakdown under high voltage.
Innovation Solution
A quantum cascade laser design that incorporates a semiconductor insulating portion with a large thickness between the metal film and the electrode, made of materials like SiO2, SiON, or III-V compound semiconductors doped with transition metals, to enhance insulation and prevent breakdown, while also using a metal film with high reflectance for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a thin insulating film is used between the metal film and the electrode, then the device structure is simpler and manufacturing is easier, but breakdown and short circuits occur under high voltage conditions
Solution Approach 1:
The patent changes the critical parameter of insulating film thickness from thin to large thickness. This parameter change directly resolves the contradiction by providing sufficient insulation strength to prevent breakdown under high voltage while maintaining manufacturing feasibility through established thin-film deposition techniques.
Solution Approach 2:
The patent employs a composite insulating structure consisting of multiple layers including SiO2, SiON, and other dielectric materials. This composite approach combines the advantages of different materials to achieve both the required electrical insulation properties and manufacturing compatibility.
2Reliability
If the insulating film thickness is increased to prevent breakdown, then reliability improves, but manufacturing complexity and difficulty increase
Solution Approach 1:
The patent optimizes the thickness parameter of the insulating film to a specific range that provides sufficient breakdown voltage resistance without excessive thickness. This balanced parameter selection improves reliability while avoiding unnecessary manufacturing complexity.
Solution Approach 2:
The patent divides the insulating structure into multiple functional layers with different thicknesses and material compositions. This segmentation allows each layer to perform its specific function optimally while keeping the overall structure manageable and manufacturable.
3Reliability
If a large thickness insulating portion is used, then breakdown and short circuits are prevented, but the device structure becomes more complex
Solution Approach 1:
The patent applies the large thickness insulating portion selectively at critical locations where high voltage stress occurs, such as between the metal film and electrode. This localized approach provides maximum reliability improvement where needed while minimizing overall device complexity.
Solution Approach 2:
The thick insulating film acts as an intermediary layer between the metal film and the electrode, providing electrical isolation and preventing direct contact. This intermediary structure resolves the contradiction by enabling high voltage operation without requiring complete structural redesign.
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
The design effectively reduces the occurrence of breakdown and short circuits, enhances the insulating properties, and improves the reliability and productivity of the quantum cascade laser by providing a robust electrical and thermal path, thus maintaining device performance under high voltage conditions.
Implementation Method 1
a semiconductor insulating portion with a large thickness between the metal film and the electrode
Implementation Method 2
a metal film with high reflectance for improved performance
Data Source
AI summary
A quantum cascade laser includes: a semiconductor device portion having a substrate, a semiconductor laminate, and a semiconductor insulating portion, the semiconductor laminate having a principal surface, the substrate having a back surface and a substrate end face, the semiconductor laminate having a laminate end face, the semiconductor insulating portion and the substrate being arranged along a reference plane intersecting the second direction, the semiconductor device portion having a front end face and a rear end face, the front end face and the rear end face being arranged in the second direction, the rear end face including the substrate end face, and the substrate end face extending along the reference plane; a first electrode disposed on the semiconductor laminate; and a metal film disposed on the rear end face, the semiconductor insulating portion and the second electrode, the metal film being apart from the first electrode.