Charge-Coupled Device With Resistive Gate Electrode for Large Pixel Charge Transfer
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Solution Overview
Problem
Charge-coupled devices face difficulties in transferring charges effectively when pixel sizes are large due to a flat potential distribution, which hinders efficient charge transfer.
Innovation Solution
A charge-coupled device with a potential inclination forming mechanism using a resistive gate electrode and transfer electrodes, where the impurity concentration difference between the barrier and charge accumulation regions allows for efficient charge transfer, even in large pixels, by creating a potential barrier and alternating potentials to facilitate charge accumulation and transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a large-sized pixel is used, then the number of charge transfer times is reduced, but the potential distribution becomes flat and charge transfer becomes difficult
Solution Approach 1:
The patent applies local quality by creating a potential inclination only in the charge transfer region through the resistive gate electrode, while maintaining other regions with standard potential distributions. This localized potential gradient enables effective charge transfer in specific areas without affecting the overall pixel structure, resolving the contradiction between large pixel size and charge transfer efficiency.
Solution Approach 2:
The resistive gate electrode acts as an intermediary element that converts electrical potential differences into a controlled potential inclination in the semiconductor substrate. This intermediary structure enables charge transfer in large pixels by mediating the potential distribution without requiring changes to the fundamental pixel architecture.
2Reliability
If a potential barrier region with low impurity concentration is formed, then reverse charge flow is prevented, but device structure becomes more complex
Solution Approach 1:
The patent merges the potential barrier function with the existing charge accumulation region by forming the barrier region adjacent to the accumulation region with a simple impurity concentration difference. This combined structure prevents reverse charge flow without requiring separate complex barrier mechanisms, maintaining structural simplicity while achieving reliable charge directionality.
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 sufficient charge transfer and accumulation across large pixels, preventing reverse flow and enhancing electric field intensity, thus overcoming the challenge of flat potential distributions in large pixel sizes.
Implementation Method 1
a charge-coupled device which converts an incident energy beam (light/X-rays) into a charge (electrons)
Implementation Method 2
a charge-coupled device transfers a generated charge using a potential inclination referred to as a fringing electric field
Data Source
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AI summary
Each pixel region PX includes a photoelectric conversion region S1, a resistive gate electrode R, a first transfer electrode T1, a second transfer electrode T2, a barrier region B positioned directly beneath the first transfer electrode T1 in a semiconductor substrate 10, and a charge accumulation region S2 positioned directly beneath the second transfer electrode T2 in the semiconductor substrate 10. An impurity concentration of the barrier region B is lower than an impurity concentration of the charge accumulation region S2, and the first transfer electrode T1 and the second transfer electrode T2 are electrically connected to each other.