Semiconductor Pixel Regions for High-Temperature Color Detection
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Solution Overview
Problem
Conventional image sensors for in-car digital cameras face challenges due to the use of organic color filters, which are unsuitable for high-temperature environments and result in reduced light intensity and inferior image quality, and existing solutions either increase leakage current or limit detection sensitivity.
Innovation Solution
A semiconductor device with three pixel regions of varying p-type well depths, allowing for the detection of short, middle, and long-wavelength light without a color filter, using a buried p-type well region and p-type well regions to optimize charge collection and reduce leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a color filter made of organic material is used for multicolor separation, then spectral characteristics for each color can be achieved, but the light intensity is attenuated by 30% or more and the filter cannot withstand high-temperature environments
Solution Approach 1:
The patent extracts and eliminates the color filter component from the system. Instead of using organic color filters that attenuate light and fail at high temperatures, the invention uses the inherent spectral response differences of multiple photoelectric conversion elements with different band gaps to achieve color separation, thereby removing the problematic color filter layer entirely
Solution Approach 2:
The patent replaces the optical filtering mechanism (mechanical/optical system using color filters) with an electrical/electronic mechanism. By utilizing photoelectric conversion elements with different spectral responses and processing their output signals electronically, the system achieves color separation without physical filters, eliminating light attenuation and temperature sensitivity issues
2Measurement precision
If multiple photoelectric conversion elements are stacked in one pixel region for multicolor separation, then spectral characteristics can be achieved, but leakage current increases and image quality deteriorates
Solution Approach 1:
The patent applies local quality by giving each photoelectric conversion element distinct spectral characteristics through different band gap energies. Each element is optimized for specific wavelength ranges, allowing color separation through selective photoelectric conversion rather than physical stacking of filters, thereby reducing leakage current while maintaining spectral discrimination capability
3Measurement precision
If the depth of p-type well region is increased to enhance detection sensitivity for long-wavelength light, then charges from deeper regions can be detected, but leakage current increases and image quality deteriorates
Solution Approach 1:
The patent changes the parameter of band gap energy across different photoelectric conversion elements. By selecting materials with different band gaps, each element responds to different wavelength ranges, enabling deep region detection for long-wavelength light without increasing leakage current, as the spectral selectivity is achieved through material properties rather than increased physical depth
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
Enables improved image quality by accurately analyzing light receiving quantities for each color without a color filter, maintaining performance in high-temperature conditions and reducing light intensity attenuation.
Implementation Method 1
The light is then converted into charges by photoelectric conversion
Data Source
AI summary
Provided are a semiconductor device capable of detecting a light of each color with high accuracy without using a color filter, particularly enhancing detection accuracy of charges obtained by photoelectric conversion of a long-wavelength light, and manufacturing and control methods thereof. The semiconductor device has a p type semiconductor substrate, and first, second and third pixel regions. These regions each include a p type well region in the p type semiconductor substrate and an n type region configuring a pn junction therewith. The p type well region of the first pixel region is thinner, from the main surface to the lowermost portion, than that of the second and third pixel regions. On the side opposite to the main surface of the p type well region of the first and second pixel regions, a buried p type well region contiguous to the p type well region is further placed.