Semiconductor Laser Conductive Oxide Sloped Side Faces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor laser elements with conductive oxide layers face issues of high resistivity leading to unsatisfactory electrical characteristics and optical confinement problems due to the high voltage required, and challenges in precisely forming dielectric layers on ridge side faces.
Innovation Solution
A semiconductor laser element is manufactured with a conductive oxide layer having sloped side faces and a dielectric layer formed on the ridge side faces, where the inclination angle of the conductive oxide layer is set to be smaller than that of the ridge, allowing for accurate dielectric layer formation and reduced electrical resistivity, thereby improving power efficiency and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conductive oxide layer is used as an electrode, then light absorption is reduced and refractive index is lowered, but electrical resistivity increases leading to high voltage and unsatisfactory electrical characteristics
Solution Approach 1:
The patent combines a conductive oxide layer with a metal layer to create a composite electrode structure. The conductive oxide layer provides low light absorption and low refractive index, while the metal layer provides low electrical resistivity. This merging of materials allows both functions to coexist in a single electrode structure.
Solution Approach 2:
The patent uses a composite structure consisting of a conductive oxide layer and a metal layer. The conductive oxide layer (such as ITO, IZO, or ZnO) is combined with a metal layer (such as Al, Mo, or W) to create an electrode that simultaneously achieves optical transparency and electrical conductivity, resolving the contradiction between light absorption and electrical characteristics.
2Reliability
If a dielectric layer is formed on the side faces of the ridge using conventional etching methods, then optical confinement is improved, but manufacturing precision deteriorates due to difficulty in stopping etching precisely at the boundary
Solution Approach 1:
The patent forms a protrusion on the conductive oxide layer before forming the dielectric layer. This protrusion serves as a pre-established boundary marker that guides the dielectric layer formation process, allowing the dielectric layer to be precisely deposited only on the ridge side faces without requiring high-precision etching to define the boundary.
Solution Approach 2:
The protrusion formed on the conductive oxide layer acts as an intermediary structure between the ridge and the dielectric layer. It provides a physical template that mediates the dielectric layer deposition process, ensuring the dielectric layer is formed with high precision on the ridge side faces without direct reliance on difficult etching boundaries.
3Ease of manufacture
If the side faces of the conductive oxide layer and semiconductor layer lie in the same plane, then manufacturing is simplified, but manufacturing precision deteriorates due to inability to precisely stop etching at the boundary
Solution Approach 1:
The patent forms a protrusion on the conductive oxide layer as a preliminary structure before subsequent processing steps. This protrusion is created by selectively removing material or by differential deposition, establishing a clear boundary feature that simplifies later dielectric layer formation while maintaining high precision at the boundary.
Data Source
Figure 1
Figure 2A~3
Figure 4a~4i
AI summary
A semiconductor laser element having; a substrate (10), a first conductivity type semiconductor layer (12), an active layer (14) and a second conductivity type semiconductor layer (16) in that order on the substrate (10), a stripe-like ridge (18) formed on the upper face of the second conductivity type semiconductor layer (16), a conductive oxide layer (20) formed on the upper face of the ridge (18), a dielectric layer (24), with a refractive index that is lower than the refractive index of the semiconductor layer (16), formed on the side faces of the ridge (18), and a metal layer (22) formed so as to cover the conductive oxide layer (20) and the dielectric layer (24), the surface of the conductive oxide layer (20) is exposed from the dielectric layer (24), and the side faces of the conductive oxide layer (20) are sloped with respect to the upper face of the ridge (18), and the inclination angle of the side faces of the conductive oxide layer (20) with respect to the normal direction is greater than the inclination angle of the side faces of the ridge (18) with respect to the normal direction.