Charge-Coupled Device With Segmented Insulating Walls
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Solution Overview
Problem
Existing charge-coupled devices (CCDs) with insulated vertical electrodes face limitations in charge transfer efficiency and power consumption, particularly in light sensors, where increasing pixel size to enhance surface area leads to higher electric power requirements and potential charge leakage between pixels.
Innovation Solution
A two-phase charge-coupled device design featuring an array of insulated electrodes with alternated longitudinal and transverse electrodes, electric insulation walls, and a doped semiconductor substrate, where electrodes are electrically coupled and biased to control potential wells, allowing efficient charge transfer with reduced power consumption and minimized charge leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If pixel size is increased to enhance surface area, then light sensitivity is improved, but electric power consumption increases and charge leakage between pixels occurs
Solution Approach 1:
The pixel array is segmented by insulating walls that vertically penetrate the semiconductor substrate, dividing the structure into isolated pixel regions. This segmentation allows each pixel to be independently controlled with lower power while preventing charge leakage between adjacent pixels, resolving the contradiction between large pixel area and low power consumption.
2Area of stationary object
If pixel size is increased to enhance surface area, then light sensitivity is improved, but charge leakage between pixels occurs
Solution Approach 1:
Insulating walls are introduced to segment the semiconductor substrate into discrete pixel regions. These walls physically isolate adjacent pixels, preventing charge leakage while allowing each pixel to maintain a large surface area for light sensitivity, thus resolving the contradiction between area and charge isolation.
Solution Approach 2:
The insulating walls act as intermediary structures between adjacent pixels, providing electrical isolation without occupying significant lateral space. This intermediary structure enables large pixel area while maintaining reliable charge isolation, resolving the contradiction between surface area and charge leakage prevention.
3Productivity
If two-phase charge transfer is implemented, then charge transfer efficiency is improved, but device complexity increases
Solution Approach 1:
The electrode structure merges longitudinal and transverse electrodes into a unified array where insulating walls create naturally forming potential wells. This merged structure simplifies the two-phase charge transfer operation while maintaining high transfer efficiency, resolving the contradiction between productivity and device complexity.
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 enables efficient two-phase charge transfer with reduced power consumption and decreased charge leakage between pixels, improving the performance of light sensors by maintaining efficient charge accumulation and transfer while minimizing dark current.
Implementation Method 1
When the substrate receives light, electron-hole pairs are photogenerated in the substrate and accumulate in potential wells defined between the electrodes
Implementation Method 2
The properly-biased electrodes of the array define a plurality of potential wells in the substrate
Implementation Method 3
The charges accumulated in the potential wells are then transferred from one potential well to an adjacent potential well by modifying, in two phases, electrode biasings
Data Source
AI summary
A charge-coupled device includes an array of insulated electrodes vertically penetrating into a semiconductor substrate. The array includes rows of alternated longitudinal and transverse electrodes. Each end of a longitudinal electrode of a row is opposite and separated from a portion of an adjacent transverse electrode of that row. Electric insulation walls extend parallel to one another and to the longitudinal electrodes. The insulation walls penetrate vertically into the substrate deeper than the longitudinal electrodes. At least two adjacent rows of electrodes are arranged between each two successive insulation walls.