Pixel Separator Depth Control for Infrared Sensor Crosstalk
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Solution Overview
Problem
Infrared sensors face challenges in suppressing crosstalk between adjacent pixels, which affects the accuracy and quality of signal electric charge reading.
Innovation Solution
A method of manufacturing a photoelectric conversion device involves forming a photoelectric conversion structure with a first semiconductor layer on a non-light-receiving surface of a light-absorbing layer and creating openings to separate each pixel, followed by forming a pixel separator of a second electrical conductivity type that extends in the thickness direction of the light-absorbing layer, using techniques like plasma doping to enhance the potential barrier and reduce signal charge movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional photoelectric conversion structure is used without deep pixel separators, then the manufacturing process is simpler, but crosstalk between adjacent pixels occurs due to insufficient suppression of signal electric charge movement
Solution Approach 1:
The patent divides the photoelectric conversion device into discrete pixel units by forming openings that penetrate through the light-absorbing layer and inserting pixel separators into these openings. This segmentation physically isolates adjacent pixels, preventing signal electric charge movement between them and suppressing crosstalk while maintaining a manageable structural complexity through systematic division.
Solution Approach 2:
The patent extends the pixel separator structure from a surface-level feature into the thickness direction of the light-absorbing layer by forming openings that penetrate through the layer. This dimensional extension creates a three-dimensional potential barrier that effectively blocks signal electric charge movement in the depth direction, achieving superior crosstalk suppression compared to conventional two-dimensional surface structures.
2Manufacturing precision
If the pixel separator is formed only at the surface level, then the manufacturing process is easier, but the potential barrier does not extend deeply enough to suppress signal charge movement between pixels
Solution Approach 1:
The patent performs preliminary etching to form openings that penetrate through the light-absorbing layer before inserting the pixel separators. This preliminary action creates predetermined pathways that guide the pixel separator placement and ensure they extend to the correct depth, achieving precise depth control while simplifying the overall manufacturing process by separating the depth definition step from the separator insertion step.
3Reliability
If no openings are formed to separate pixels, then the photoelectric conversion structure remains intact and simpler, but signal electric charges can move between adjacent pixels causing crosstalk
Solution Approach 1:
The patent extracts material from the light-absorbing layer by forming openings that penetrate through it, creating physical separations between adjacent pixels. This extraction removes the conductive path that would otherwise allow signal electric charge movement between pixels, thereby suppressing crosstalk and improving signal reading accuracy while adding necessary structural elements for pixel isolation.
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 approach effectively suppresses crosstalk between pixels, improving the accuracy and quality of signal reading by expanding the potential barrier deeper into the light-absorbing layer, thereby enhancing the performance of the photoelectric conversion device.
Implementation Method 1
expand a potential barrier by the pixel separator to a deeper region of the light-absorbing layer, which makes it possible for the photoelectric conversion device to more firmly suppress movement of signal electric charges between pixels
Data Source
AI summary
A method of manufacturing a photoelectric conversion device includes: forming a photoelectric conversion structure in which a first semiconductor layer of a first electrical conductivity type is provided on a non-light-receiving surface, on side opposite to a light-receiving surface, of a light-absorbing layer including a compound semiconductor; forming an opening by etching at least a portion of the photoelectric conversion structure, the opening that separates the photoelectric conversion structure for each pixel; and forming a pixel separator of a second electrical conductivity type on the light-absorbing layer exposed in the opening, the pixel separator extending in a thickness direction of the light-absorbing layer.