Infrared Light Receiving Device with Segmented Superlattice
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Solution Overview
Problem
Existing semiconductor light receiving devices with III-V semiconductor superlattice layers suffer from high generation/recombination current, which hampers light receiving sensitivity due to the volume of the superlattice layer, and current fabrication methods do not effectively reduce this current.
Innovation Solution
The infrared light receiving device features a laminate body with a first superlattice layer of n-type conductivity and a semiconductor region of p-type conductivity, arranged sequentially on a supporting base, with recess portions of different depths to reduce the volume of the superlattice layer and interconnect semiconductor mesas, thereby minimizing generation/recombination current and enhancing light receiving sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the volume of the superlattice layer is increased, then the light receiving sensitivity is improved, but the generation/recombination current increases
Solution Approach 1:
The superlattice layer is divided into a first superlattice layer and a second superlattice layer with different functions. The first superlattice layer forms a heterojunction with the substrate and has n-type conductivity, while the second superlattice layer serves as the light receiving layer with larger volume. This segmentation allows the light receiving function to be separated from the heterojunction formation function, enabling the light receiving layer to have sufficient volume for high sensitivity without requiring the entire superlattice structure to be large.
Solution Approach 2:
Different regions of the superlattice structure are assigned different properties. The first superlattice layer has n-type conductivity and forms the heterojunction, while the second superlattice layer is optimized for light absorption. The recess portions are strategically positioned to remove material only where not needed for light receiving, preserving the volume of the light receiving layer while reducing generation/recombination current in non-critical areas.
2Object-generated harmful factors
If the volume of the superlattice layer is reduced, then the generation/recombination current is lowered, but the light receiving sensitivity deteriorates
Solution Approach 1:
By dividing the superlattice into functional segments, the invention allows selective reduction of material volume. The first superlattice layer can be made thinner or have recesses without affecting the light receiving capability of the second superlattice layer, thus lowering generation/recombination current while maintaining sensitivity.
Solution Approach 2:
The recess portions are strategically placed in the first superlattice layer where they do not interfere with the light receiving function of the second superlattice layer. This localized modification reduces the volume of material contributing to generation/recombination current while preserving the light receiving volume where it matters most.
3Ease of manufacture
If conventional fabrication methods are used, then the manufacturing process is simple, but the generation/recombination current cannot be effectively reduced
Solution Approach 1:
The recess portions are formed in the superlattice layer before final device assembly and testing. This preliminary structuring allows the generation/recombination current to be reduced as part of the fabrication process itself, rather than requiring additional post-processing steps to mitigate the harmful current.
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 solution effectively reduces the volume of the superlattice layer, lowering generation/recombination current and improving the light receiving sensitivity of the semiconductor light receiving elements by connecting semiconductor mesas through the first superlattice layer, allowing for better carrier flow to the electrode.
Implementation Method 1
The first superlattice layer has a type-II superlattice structure and forms a heterojunction with the supporting base
Implementation Method 2
the laminate body having an array of semiconductor mesas for photodiodes
Data Source
AI summary
An infrared light receiving device includes: a structure having a supporting base and a laminate body, the laminate body including a first superlattice layer, a second superlattice layer and a semiconductor region, the first superlattice layer, the second superlattice layer and the semiconductor region being arranged sequentially on the supporting base, and the laminate body having an array of semiconductor mesas for photodiodes and a recess defining the array of semiconductor mesas; and a first electrode connected to the first superlattice layer. The first superlattice layer has an n-type conductivity. The semiconductor region has a p-type conductivity. The first superlattice layer has a type-II superlattice structure and forming a heterojunction with the supporting base. The recess has first and second recess portions. The second recess portion has a bottom in the first superlattice layer. The first recess portion has a depth larger than that of the second recess portion.