Stacked Photodiode Layout Without Through-Electrode Constraints
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing photoelectric conversion apparatuses face limitations in design freedom due to through electrodes, which restrict the arrangement of transistors and the configuration of voltage supply to semiconductor substrates, affecting Dark Count Rate (DCR) and signal processing.
Innovation Solution
A photoelectric conversion apparatus with a stacked substrate configuration, where a sensor substrate with photoelectric conversion elements and a circuit substrate with signal processing units are connected, allowing for flexible placement of transistors and independent voltage supply to substrates, enhancing signal processing and reducing DCR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a through electrode is used to supply voltage to the semiconductor substrate, then voltage supply is achieved, but the degree of freedom of transistor arrangement is limited
Solution Approach 1:
The patent divides the voltage supply function into two separate electrodes: a first electrode on the first surface and a second electrode on the second surface of the semiconductor substrate. This segmentation eliminates the need for through-electrodes that penetrate the entire substrate, thereby freeing up space and design flexibility for transistor arrangement while maintaining effective voltage supply across the substrate.
Solution Approach 2:
Instead of using a single through-electrode approach (one-dimensional penetration), the patent utilizes both surfaces of the substrate (two-dimensional approach) to supply voltage. The first electrode is disposed on the first surface and the second electrode on the second surface, allowing transistors to be arranged more freely in the planar dimension without being constrained by through-electrode pathways.
2Adaptability or versatility
If a through electrode structure is implemented, then voltage supply is achieved, but design freedom of voltage supply configuration is limited
Solution Approach 1:
The voltage supply system is segmented into two independent electrodes located on opposite surfaces of the substrate. This allows independent optimization of each electrode's configuration and connection path, enabling greater design freedom in how voltage is supplied to different regions of the semiconductor device without the constraints of a single through-electrode structure.
3Productivity
If transistors are arranged with through electrode constraints, then device fabrication is simplified, but signal processing efficiency is reduced
Solution Approach 1:
By utilizing both surfaces of the substrate for electrode placement rather than relying on through-electrodes, the patent enables more flexible transistor positioning and routing. This dimensional approach allows transistors to be arranged optimally for signal processing performance without being constrained by vertical through-electrode pathways, improving signal processing efficiency while maintaining manufacturability.
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 increases design flexibility, improves signal processing efficiency, and reduces pixel size while maintaining effective avalanche multiplication and avalanche current generation.
Implementation Method 1
The difference between a potential applied to the first conductive line and a potential applied to the second conductive line is greater than or equal to a breakdown voltage
Data Source
AI summary
An apparatus includes a photodiode in a first substrate having a first surface and a second surface opposite the first surface. The photodiode includes a first region of a first conductivity type at a first depth, a second region of a second conductivity type at a second depth deeper than the first depth with respect to the second surface, a third region at a third depth deeper than the second depth with respect to the second surface, a fourth region in contact with the third region, a first conductive line connected to the first region and disposed adjacent to the second surface to read a signal from the first region, and a second conductive line provided adjacent to the first surface. The difference between potentials applied to the first and second conductive lines is the breakdown voltage or greater.