Light Receiving Element Array Structure for Crosstalk Isolation
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Solution Overview
Problem
Existing light receiving element arrays face issues with crosstalk due to the lack of effective separation between light receiving elements, leading to increased leakage of electric current between adjacent elements when light is incident.
Innovation Solution
A light receiving element array is designed with a laminated semiconductor structure that includes a light absorbing layer and window layers of a first conductivity type, where a second conductivity type region extends into the light absorbing layer and surrounds the window layers, reducing crosstalk by preventing electron and hole movement between elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If light receiving elements are arranged closely to increase array density, then productivity and area utilization are improved, but crosstalk between adjacent elements increases due to insufficient separation
Solution Approach 1:
The patent introduces separating structures (such as isolation layers or etched grooves) that divide the light receiving element array into independent sections. These separating structures physically segment the array, preventing electrical and optical interference between adjacent elements while maintaining high density arrangement.
Solution Approach 2:
The patent applies different structural characteristics to different regions of the array. Specifically, separating structures are introduced only in the regions between adjacent light receiving elements, while the light receiving elements themselves maintain their original high-performance structure. This localized modification reduces crosstalk without compromising the overall array density.
2Reliability
If separating structures are introduced to reduce crosstalk, then reliability is improved, but device complexity increases due to additional manufacturing steps
Solution Approach 1:
The patent combines the formation of separating structures with existing manufacturing processes. For example, the separating structures are formed using the same epitaxial growth or etching processes that are already used for creating the light receiving elements themselves, rather than introducing entirely new process steps.
Solution Approach 2:
The separating structures serve multiple functions simultaneously: they provide electrical isolation between elements, act as etch masks during fabrication, and can serve as bonding interfaces for subsequent processing steps. This multi-functionality reduces the need for additional dedicated structures.
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 significantly reduces crosstalk and dark current, improving the efficiency and performance of the light receiving element array by suppressing electric current leakage between adjacent elements.
Implementation Method 1
a second conductivity type region that extends into the light absorbing layer and surrounds the window layers, reducing crosstalk by preventing electron and hole movement between elements
Implementation Method 2
a light absorbing layer and a plurality of window layers
Data Source
AI summary
A light receiving element array includes a substrate and a laminated semiconductor structure that is formed on the substrate. The laminated semiconductor structure includes a light absorbing layer that is disposed above the substrate and a plurality of window layers of a first conductivity type that are formed apart from each other on the light absorbing layer. Inside the laminated semiconductor structure, there is formed, for each window layer, a first of second conductivity type region that extends into the light absorbing layer from a surface of the window layer at an opposite side to the light absorbing layer. Inside the light absorbing layer, there is formed a second of second conductivity type region that is disposed such as to surround each of the plurality of window layers in plan view and extends from a surface of the light absorbing layer at an opposite side to the substrate toward a surface of the light absorbing layer at the substrate side.