InP Semiconductor Laser Active Layer Waveguide Manufacturing
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Solution Overview
Problem
Semiconductor lasers using group III-V compound semiconductors face challenges in manufacturing methods and structure improvements, particularly with the oxidation of aluminum in the active layer leading to deterioration and the need for effective antioxidant measures.
Innovation Solution
A method for manufacturing semiconductor devices involves growing a first semiconductor layer on an inclined substrate with a specific angle, followed by a second semiconductor layer, using group III-V compound semiconductors, which enhances the semiconductor laser's performance by reducing oxidation and improving the active layer's characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cover layer is added to cover the active layer to prevent oxidation of Al, then the active layer is protected from oxidation, but the device structure becomes more complex and manufacturing process is extended
Solution Approach 1:
An intermediate layer is introduced between the active layer and the cover layer. This intermediate layer serves as a buffer that prevents direct contact between the Al-containing active layer and the cover layer, thereby preventing oxidation while maintaining a relatively simple overall structure. The intermediate layer acts as a mediator that solves the oxidation problem without requiring direct modification of the active layer or cover layer designs.
2Stability of the object's composition
If the substrate inclination angle is increased to improve epitaxial growth quality, then crystallinity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The substrate inclination angle is optimized to a specific range (0.5° to 1.0°) rather than using a perfectly flat substrate or a highly inclined substrate. This parameter optimization achieves good crystallinity while avoiding the need for extremely high angular precision in manufacturing. The moderate angle provides sufficient epitaxial growth quality improvement without imposing excessive precision requirements.
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 approach results in semiconductor devices with improved characteristics, including reduced resistance and stable photo luminescence full width at half maximum (PL FWHM), maintaining excellent crystallinity and enabling high-speed operation.
Implementation Method 1
a first semiconductor layer is grown in a first region of a substrate, and a second semiconductor layer is further grown over the first semiconductor layer
Data Source
AI summary
To improve characteristics of a semiconductor device (semiconductor laser), an active layer waveguide (AWG) comprised of InP is formed over an exposed part of a surface of a substrate having an off angle ranging from 0.5° to 1.0° in a [1-1-1] direction from a (100) plane to extend in the [0-1-1] direction. A cover layer comprised of p-type InP is formed over the AWG with a V/III ratio of 2000 or more. Thereby, it is possible to obtain excellent multiple quantum wells (MQWs) by reducing a film thickness variation of the AWG. Moreover, the cover layer having side faces where a (0-11) plane almost perpendicular to a substrate surface mainly appears can be formed. A sectional shape of a lamination part of the cover layer and the AWG becomes an approximately rectangular shape. Therefore, an electrification region can be enlarged and it is possible to reduce a resistance of the semiconductor device.