Optical Sensor Charge Transfer Using Avalanche and Potential Gradient
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Solution Overview
Problem
Optical sensors face challenges in transferring charges efficiently across large light-receiving areas due to the time required for charge movement in the charge generation region, leading to potential delays in charge transfer to the charge collection region.
Innovation Solution
Incorporating an avalanche multiplication region and a gradient potential energy formation region in the charge generation region, along with strategically placed transfer gate electrodes, to enhance charge transfer speed and sensitivity, while minimizing noise and increasing dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the area of the charge generation region is enlarged to broaden the light-receiving region, then the light-receiving capability is improved, but the charge transfer speed deteriorates due to increased charge movement time
Solution Approach 1:
The charge generation region is divided into two distinct regions with different properties: an avalanche multiplication region with high electric field for rapid charge generation and multiplication, and a gradient potential energy formation region with gradually decreasing potential energy to accelerate charge movement. This local differentiation allows each region to optimize for its specific function, resolving the contradiction between large area and fast transfer speed
Solution Approach 2:
The gradient potential energy formation region creates a dynamic electric field distribution where potential energy decreases gradually from the avalanche multiplication region toward the charge collection region. This dynamic potential gradient continuously accelerates charges during their movement, maintaining high transfer speed across the entire large-area charge generation region
2Area of stationary object
If the area of the charge generation region is enlarged to broaden the light-receiving region, then the light-receiving capability is improved, but the charge transfer time increases
Solution Approach 1:
By creating a gradient potential energy formation region adjacent to the avalanche multiplication region, the patent establishes a localized acceleration zone that reduces charge transfer time. The gradient structure ensures that charges experience continuous acceleration throughout their movement across the large area, minimizing the time loss that would otherwise occur in a uniform field
Solution Approach 2:
The gradient potential energy formation region is positioned to receive charges immediately after they are generated in the avalanche multiplication region. This preliminary acceleration structure is pre-configured to catch and accelerate charges before they traverse the full distance to the charge collection region, reducing overall transfer time across the large area
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 high-speed charge transfer across large light-receiving areas, improving sensitivity and dynamic range by utilizing avalanche multiplication and gradient potential energy to accelerate charge movement and suppress noise.
Implementation Method 1
a charge generation region that generates charges in response to incident light... an avalanche multiplication region that causes avalanche multiplication
Implementation Method 2
a gradient potential energy formation region that forms gradient potential energy in the charge generation region, the gradient potential energy being gradient so that potential energy becomes lower as approaching the transfer region
Data Source
AI summary
Provided is an optical sensor including: a charge generation region that generates charges in response to incident light; a charge collection region to which charges generated in the charge generation region are transferred; and at least one transfer gate electrode disposed on a transfer region between the charge generation region and the charge collection region. The charge generation region includes an avalanche multiplication region that causes avalanche multiplication, and a gradient potential energy formation region that forms gradient potential energy that is gradient so that potential energy becomes lower as approaching the transfer region in the charge generation region.