Stacked Photoelectric Conversion Layer for Color Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional color solid-state imaging devices with mosaic color filters suffer from low light utilization efficiency and sensitivity, leading to low resolution and false colors due to the absorption of incident light and the need for complex manufacturing processes and costly production.
Innovation Solution
A hybrid photoelectric-conversion-layer-stack-type color solid-state imaging device with a semiconductor substrate, a photoelectric conversion layer for green light, and photodiodes in the substrate for blue and red light detection, utilizing inorganic color filter layers made of amorphous silicon or polysilicon to enhance color separation and light utilization efficiency without additional color filters over the photodiodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If mosaic color filters are arranged on photoelectric conversion pixels, then color signals can be obtained, but light utilization efficiency and sensitivity are low because 2/3 of incident light is absorbed by the color filters
Solution Approach 1:
The patent transitions from a two-dimensional mosaic arrangement of color filters on the surface to a three-dimensional stacked structure where photoelectric conversion layers are arranged vertically at different depths in the semiconductor substrate. This allows incident light to be utilized by multiple layers simultaneously, with each layer detecting different wavelengths based on its depth, thereby dramatically improving light utilization efficiency while maintaining color signal accuracy.
Solution Approach 2:
The patent divides the photoelectric conversion function into multiple separate layers, each optimized for detecting specific color wavelengths. The blue-sensitive layer, green-sensitive layer, and red-sensitive layer are segmented and positioned at different depths, allowing each segment to specialize in detecting its target wavelength range without interference from other color filters.
2Loss of energy
If three layers of photoelectric conversion layers are stacked on the semiconductor substrate, then light utilization efficiency improves, but manufacturing complexity increases and production yields decrease
Solution Approach 1:
The patent combines multiple photoelectric conversion layers and their associated color filter functions into a single integrated semiconductor substrate structure. The blue-sensitive, green-sensitive, and red-sensitive layers are merged into one continuous substrate with vertical interconnections, eliminating the need for separate manufacturing processes for each layer and significantly simplifying production while maintaining high light utilization efficiency.
3Measurement precision
If photodiodes detect light at different depths in the silicon substrate, then color signals with different spectra are obtained, but additional color filters over photodiodes are needed which complicates the structure
Solution Approach 1:
The patent extracts the color filtering function from separate components and integrates it directly into the photoelectric conversion layers themselves. Each photoelectric conversion layer is designed with inherent spectral sensitivity characteristics that act as built-in color filters, eliminating the need for additional separate color filter components over the photodiodes and simplifying the overall device structure.
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 improves color separation performance and light utilization efficiency, simplifies manufacturing, and increases the signal-to-noise ratio, enabling high-resolution, high-sensitivity color images with reduced production costs.
Implementation Method 1
a photoelectric conversion layer laid over the semiconductor substrate, for absorbing light of a first color among three primary colors and thereby generating photocharges
Implementation Method 2
plural first photodiodes arranged in the surface layer of the substrate, for detecting mixed light of second and third colors among the three primary colors that has passed through the photoelectric conversion layer
Implementation Method 3
utilizing inorganic color filter layers made of amorphous silicon or polysilicon to enhance color separation and light utilization efficiency
Data Source
AI summary
A color solid-state imaging device including: a semiconductor substrate; a photoelectric conversion layer provided over the semiconductor substrate, for absorbing light of a first color among three primary colors so as to generate photocharges; plural charge storage regions arranged in a surface layer of the semiconductor substrate, for storing the photocharges; plural first photodiodes arranged in the surface layer of the substrate, for detecting mixed light of second and third colors among the three primary colors that has passed through the photoelectric conversion layer and for storing generated photocharges; plural second photodiodes arranged in the surface layer of the semiconductor substrate, for detecting light of the second color of the mixed light that has passed through the photoelectric conversion layer and for storing generated photocharges; color filter layers provided over the second photodiodes, for interrupting light of the third color; and signal reading units as defined herein.