Radiation Detector Pixel Layout for Charge-Induced Noise Control
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Solution Overview
Problem
Radiation detectors suffer from degradation due to retained charges in the insulating layer, leading to fluctuations in pixel output and increased dark current, which affects detection sensitivity and image quality.
Innovation Solution
The layout of signal wiring and amplification transistor is designed to avoid overlap, reducing the electric field and minimizing the influence of retained charges, thereby improving radiation resistance and detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If signal wiring overlaps with amplification transistor, then device complexity is reduced, but retained charges in insulating layer cause fluctuations in pixel output and increased dark current
Solution Approach 1:
The patent resolves the layout conflict by transitioning from a two-dimensional planar arrangement to a three-dimensional stacked configuration. The signal wiring is positioned in a lower layer while the amplification transistor is placed in an upper layer, allowing both components to coexist without overlapping in the plan view. This vertical separation eliminates the harmful electric field interaction while maintaining compact device footprint.
2Manufacturing precision
If signal wiring overlaps with amplification transistor, then manufacturing precision requirements are reduced, but detection sensitivity decreases due to retained charges
Solution Approach 1:
By stacking the signal wiring and amplification transistor in different vertical layers, the patent eliminates planar overlap without requiring extremely precise lateral alignment. This approach reduces manufacturing precision demands while simultaneously improving detection sensitivity by removing the source of charge-induced noise.
3Reliability
If signal wiring is positioned away from amplification transistor, then radiation resistance is improved, but device area increases
Solution Approach 1:
The patent achieves both radiation resistance and compact area by utilizing vertical stacking. The signal wiring and amplification transistor are separated in the vertical dimension rather than the horizontal dimension, maintaining close proximity in the plan view for small pixel area while ensuring sufficient vertical separation for reduced electric field interaction and improved radiation resistance.
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 design enhances detection sensitivity and reduces noise, fixed pattern noise, and image persistence, enabling high-speed imaging with improved radiation resistance.
Implementation Method 1
a radiation detection element configured to convert radiation into charges
Data Source
AI summary
A radiation detector comprising: a pixel array in which pixels each having a radiation detection element configured to convert radiation into charges and an amplification transistor configured to amplify a signal from the radiation detection element and output the amplified signal are arrayed in a matrix shape; and signal wiring provided for each pixel column, wherein a pixel isolation structure formed to surround the radiation detection element in a plan view is provided, and the amplification transistor is arranged inside a region defined by the pixel isolation structure in a plan view.