Three-Region Photodetector for Pixel-Array Light Detection
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Solution Overview
Problem
Existing photodetectors face challenges in enhancing the detection characteristics of incident light on pixel arrays, particularly in imaging and sensing applications.
Innovation Solution
A photodetector design featuring a semiconductor substrate with specific electrical conduction type regions and electrodes, including a pixel separation layer, to enhance light absorption and electrical coupling for improved detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional photodetector structure is used, then the device can be manufactured with standard processes, but the detection characteristics of incident light on the pixel array are insufficient
Solution Approach 1:
The photodetector structure is segmented into distinct functional regions: a first region with first conductivity type, a second region with second conductivity type, and a third region with third conductivity type. This segmentation allows each region to perform specific functions (light absorption, charge generation, charge collection) that collectively improve detection characteristics while maintaining manufacturability through standardized semiconductor processing techniques.
Solution Approach 2:
Different regions of the photodetector are assigned different electrical conduction types (first, second, and third conductivity types) to create localized functional properties. The first region collects electrons, the second region collects holes, and the third region absorbs incident light and generates charge carriers. This local differentiation of electrical properties enhances light detection efficiency without requiring complex external systems.
2Measurement precision
If the third region is positioned between the first and second regions to absorb incident light, then light absorption efficiency is improved, but the wiring structure becomes more complex requiring electrodes to extend through the substrate
Solution Approach 1:
The first electrode extends from the second surface (back surface) of the semiconductor substrate in the thickness direction to reach the first region on the bottom surface. This vertical extension through the substrate thickness dimension allows electrical connection to the first region without interfering with the planar arrangement of light-absorbing regions, thereby improving light absorption efficiency while managing wiring complexity through three-dimensional spatial arrangement.
3Adaptability or versatility
If pixels are arranged in a matrix for imaging applications, then the imaging capability is enabled, but cross-talk between adjacent pixels increases
Solution Approach 1:
The pixel separation layer is positioned between adjacent photodetector structures to act as an intermediary barrier. This insulating layer prevents electrical and optical cross-talk between neighboring pixels in the matrix arrangement, thereby enabling imaging capability while maintaining signal isolation and detection reliability across the pixel array.
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 design allows for increased detection capabilities and efficient light absorption, enabling better performance in imaging and sensing tasks.
Implementation Method 1
The third region absorbs incident light
Implementation Method 2
a photodetector that detects the amount of incident light as a dynamic current change or a dynamic voltage change
Data Source
AI summary
A photodetector according to an embodiment of the present disclosure including a plurality of photoelectric conversion sections that is provided to a semiconductor substrate. The photoelectric conversion sections each include a first region of a first electrical conduction type that is provided on a first surface side of the semiconductor substrate, a second region of a second electrical conduction type that is provided on a second surface side of the semiconductor substrate opposite to the first surface, a third region of a third electrical conduction type that is provided in a region between the first region and the second region of the semiconductor substrate, a first electrode that extends from the second surface in a thickness direction of the semiconductor substrate, a pixel separation layer having an insulation property, and a second electrode that is electrically coupled to the second region from the second surface side. The third region absorbs incident light. The first electrode is electrically coupled to the first region on a bottom surface. The pixel separation layer is provided to a side surface of the first electrode.