Avalanche Photodiode Pixel Layout for Low-Noise Quenching
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Solution Overview
Problem
In photoelectric conversion devices using avalanche photodiodes, the proximity of quenching resistive elements to the APD leads to variations in electrostatic potential, causing noise and local electric field concentration, especially in minute pixel configurations.
Innovation Solution
The resistive element is positioned farther away from the semiconductor layer surface compared to the wiring structure, preventing electrostatic interference and reducing noise by maintaining a consistent electric field distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the resistive element is disposed near the avalanche photodiode on the semiconductor layer surface, then the device complexity is reduced and integration is improved, but noise increases due to electrostatic potential variations and local electric field concentration
Solution Approach 1:
The patent applies dimensional separation by moving the resistive element from the same plane (2D proximity) to a different vertical level (3D separation). Specifically, the resistive element is disposed on an insulating film that is positioned at a different height than the semiconductor layer surface, creating vertical separation while maintaining horizontal proximity. This dimensional transition resolves the contradiction by reducing electrostatic interference (lowering noise) without significantly increasing device footprint or complexity.
2Manufacturing precision
If the resistive element is disposed close to the avalanche photodiode, then manufacturing precision requirements are simplified, but measurement precision deteriorates due to electrostatic potential variations
Solution Approach 1:
The patent introduces an insulating film as an intermediary layer between the semiconductor layer and the resistive element. This intermediary structure serves multiple functions: it electrically isolates the resistive element from the semiconductor layer (reducing noise coupling), provides a platform for disposing the resistive element in proximity without direct contact, and maintains manufacturing simplicity while improving measurement precision by reducing electrostatic interference.
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 noise and facilitates the integration of pixels by minimizing electrostatic interference and maintaining a uniform electric field, enhancing the signal-to-noise ratio and reducing timing jitter.
Implementation Method 1
photoelectric conversion device incorporating an avalanche photodiode (APD)
Implementation Method 2
avalanche photodiode (APD) to operate in a Geiger mode
Implementation Method 3
a resistive element connected to the avalanche photodiode
Data Source
AI summary
A device includes a first substrate including a first layer including a first surface and a second surface, and a first wiring structure located on the first layer. The device includes an avalanche photodiode located on the first layer, and a resistive element connected to the avalanche photodiode. The first wiring structure includes a wire to supply a first voltage to the avalanche photodiode. A distance between the resistive element and the first surface of the first layer is greater than a distance between the wire and the first surface of the first layer.