Optical Semiconductor Ridge Structure Without Embedded Layers
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Solution Overview
Problem
In optical semiconductor integrated elements with embedded layers, crystal defects in the light absorption layer of the photodetector section lead to deteriorated photo detecting character and reliability.
Innovation Solution
The optical semiconductor integrated element is designed without a semiconductor embedded layer on the side surfaces of the light confining layer, cladding layer, and contact layer, which eliminates crystal defects in the InGaAs or InGaAsP contact layer used as a light absorption layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a semiconductor embedded layer is provided on the side surface of the light confining layer, cladding layer, and contact layer, then light confinement is improved, but crystal defects (stacking defects/anti-phase domain) occur in the contact layer used as light absorption layer
Solution Approach 1:
The patent removes the semiconductor embedded layer from the side surface of the light confining layer, cladding layer, and contact layer. This extraction eliminates the source of crystal defects (stacking defects/anti-phase domains) that occur when the contact layer is grown on the embedded layer, thereby improving photo detecting character while maintaining light confinement through the ridge structure design
2Adaptability or versatility
If the contact layer is grown on the embedded layer surface, then integration of laser and photodetector is achieved, but stacking defects occur due to non-flat surface morphology of embedded layer
Solution Approach 1:
The patent extracts/removes the semiconductor embedded layer from the region where the contact layer is formed. This eliminates the non-flat surface morphology issue of the embedded layer that causes stacking defects, allowing the contact layer to be grown on a flat surface (directly on the cladding layer) while maintaining the integrated laser-photodetector structure through alternative design arrangements
Solution Approach 2:
The patent applies different structural configurations to different regions: the laser section maintains the embedded layer structure for optimal light confinement, while the photodetector section eliminates the embedded layer on side surfaces to prevent crystal defects in the contact layer. This local differentiation allows each section to have optimal crystal quality for its specific function
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 suppresses the deterioration of photo detecting character and enhances the reliability of the photodetector by eliminating crystal defects and ensuring high light confinement and absorption.
Implementation Method 1
a light confining layer which confines light
Implementation Method 2
a contact layer formed of an InGaAs layer or an InGaAsP layer... the contact layer of the photodetector section is a light absorption layer
Data Source
AI summary
An optical semiconductor integrated element comprises a laser section and a photodetector section which are arranged on the same semiconductor substrate, the laser section and the photodetector section each have a light confining layer which confines light, a cladding layer, and a contact layer formed of an InGaAs layer or an InGaAsP layer, the light confining layer of the laser section is an active layer, the contact layer of the photodetector section is a light absorption layer, each cladding layer is a ridge structure having a shape in which a width at a side of the light confining layer is narrower than a width at a side of the contact layer in a cross-section which is perpendicular to the optical axis, and on a side surface of the light confining layer, the cladding layer and the contact layer, a semiconductor embedded layer is not provided.