Waveguide Photonic Structure Using P-Type Pillars to Limit Light Absorption
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Solution Overview
Problem
The existing photonic devices require a thick P-type semiconductor layer, which leads to significant absorption of light radiation and complicates manufacturing due to high surface topology and lengthy etching processes.
Innovation Solution
The photonic device employs P-type semiconductor pillars separated by an encapsulation material of lower optical index, shaping the optical mode to avoid absorption by metal pads and reducing the thickness of the P-type layer, eliminating the need for blocking layers and high-temperature epitaxy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick P-type semiconductor layer is used, then effective light radiation is achieved, but light absorption by metal pads increases and manufacturing complexity increases
Solution Approach 1:
The P-type semiconductor layer is segmented into multiple P-type semiconductor layers with different thicknesses, arranged in sequence. This segmentation allows the optical mode to be shaped to avoid metal pads while maintaining effective light radiation, thus resolving the contradiction between radiation efficiency and manufacturing complexity
Solution Approach 2:
Different regions of the P-type semiconductor structure have different thicknesses optimized for their specific functions: thicker regions for effective light radiation and thinner regions for avoiding metal pad absorption. This local optimization resolves the contradiction by making each region serve its specific purpose efficiently
2Reliability
If a thick P-type semiconductor layer is used, then light radiation is maintained, but etching time increases and surface topology becomes complex
Solution Approach 1:
The thick P-type layer is divided into multiple thinner layers with varying thicknesses. This segmentation reduces the total etching time required while maintaining the optical functionality, as the etching process can be optimized for each thinner layer rather than requiring complete removal of a single thick layer
Solution Approach 2:
The thickness parameter of the P-type semiconductor layer is varied across different regions and layers, creating a gradient structure. This parameter change allows optimization of both light radiation and etching characteristics, reducing etching time while maintaining radiation effectiveness
3Reliability
If a thick P-type semiconductor layer is used, then light radiation is achieved, but absorption of light by metal pads increases
Solution Approach 1:
The P-type semiconductor structure is segmented into multiple layers with different thicknesses, creating an optical mode profile that avoids the metal pad regions. This segmentation prevents light energy from being absorbed by metal pads while maintaining effective light radiation from the active region
Solution Approach 2:
The potential harm of light absorption by metal pads is converted into a benefit by using the varying thickness of P-type layers to shape the optical mode. The structure that would normally cause absorption is transformed into an optical confinement mechanism that directs light away from metal pads and toward the waveguide
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 enhances efficiency by limiting light absorption and simplifies manufacturing, achieving reduced thickness and flat surface topology while maintaining effective light radiation.
Implementation Method 1
The P-type semiconductor material has a first optical index and the P-type pillars are separated from each other by an encapsulation material having a second optical index, lower than the first
Implementation Method 2
a wave guide extending in a plane along a main direction of propagation of the optical mode
Implementation Method 3
an active region formed by a stack of layers of III-V materials forms the optical amplification medium of a laser... to electrically pump the amplifying medium in order to allow light generation
Data Source
AI summary
A photonic device for providing light radiation comprises a wave guide, an N-type semiconductor layer covering the wave guide and an active region formed by a stack of layers made of III-V materials. The photonic device also comprises a plurality of P-type semiconductor pillars arranged on and in contact with the active region. At least a first metal pad is in ohmic contact with the free portion of the N-type layer and at least a second metal pad is in ohmic contact with the P-type pillars.