Pixel Amplifier Layout for Lower Capacitance Image Sensors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The element separation region in imaging devices requires a wider diffusion layer in the horizontal direction, increasing wiring between the floating diffusion and the amplifier transistor, which leads to higher parasitic capacitance.
Innovation Solution
The imaging device incorporates a configuration where adjacent pixels share amplifying elements and power storage units, with a shorter distance between the power storage unit and the amplifying element, and uses a through trench and element separation region to reduce parasitic capacitance, including a conductive portion extending across the trench for connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an element separation region is arranged in a pixel to prevent short-circuiting, then reliability is improved, but the width of the diffusion layer increases, leading to increased wiring length and parasitic capacitance
Solution Approach 1:
The patent moves the amplifying element from the same plane as the floating diffusion to an adjacent pixel location, utilizing spatial reconfiguration across pixel boundaries. This dimensional shift allows the wiring to connect through a shorter path via the through-trench, reducing parasitic capacitance while maintaining element isolation
2Reliability
If an element separation region is arranged in a pixel to prevent short-circuiting, then reliability is improved, but device complexity increases due to additional isolation structures
Solution Approach 1:
The patent merges the element separation function with the pixel boundary structure by placing the amplifying element in an adjacent pixel and using the through-trench to connect across pixel boundaries. This consolidation eliminates the need for separate isolation structures within each pixel, reducing overall device complexity while maintaining reliability
3Object-affected harmful factors
If the distance between the power storage unit and the amplifying element is reduced, then parasitic capacitance is decreased, but manufacturing precision requirements increase
Solution Approach 1:
The patent establishes the amplifying element position in advance within the adjacent pixel structure, and designs the through-trench connection path beforehand. This preliminary positioning allows for optimized spacing that minimizes parasitic capacitance while maintaining feasible manufacturing tolerances through pre-planned alignment features
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
This configuration reduces parasitic capacitance and enhances conversion efficiency by minimizing the length of conductive portions, thereby improving the performance of the imaging device.
Implementation Method 1
a first photoelectric conversion element; a first transfer element that enables a conductive state or a non-conductive state between the first photoelectric conversion element and the first power storage unit
Data Source
AI summary
In order to solve the foregoing problem, the present disclosure provides an imaging device composed of a plurality of pixels, wherein a first pixel among the plurality of pixels includes: a first photoelectric conversion element; a first power storage unit; a first transfer element that enables a conductive state or a non-conductive state between the first photoelectric conversion element and the first power storage unit; and a first amplifying element that amplifies an image signal on the basis of a charge stored by photoelectric conversion in at least any of adjacent pixels, including a second pixel, that are adjacent to the first pixel, the second pixel including: a second amplifying element that amplifies an image signal based on a charge stored in the first power storage unit by photoelectric conversion of the first photoelectric conversion element, and a second distance between the first power storage unit and the second amplifying element is shorter than a first distance between the first power storage unit and the first amplifying element.