Semiconductor Radiation Detector with Trench Charge Collection
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Solution Overview
Problem
Semiconductor radiation detectors with modified internal gates face challenges in visible light detection due to high power consumption, manufacturing complexity, and image quality degradation, particularly in portable consumer applications, where a thick substrate is required for deep penetration but leads to high voltage needs and increased costs.
Innovation Solution
A semiconductor radiation detector design that removes the conductive backside layer, using channel stops and trench structures to collect secondary charges inside the active area, allowing for front illumination and improved blue response with a structured modified internal gate layer, reducing the need for high voltage and enhancing signal charge separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick substrate is used to enable detection of deeply penetrating radiation, then detection capability for deep penetration radiation is improved, but power consumption and voltage requirements increase
Solution Approach 1:
The patent removes the conductive backside layer from the detector structure, extracting the component that was responsible for transporting secondary charges outside the active area. This simplification eliminates the need for high voltage biasing while maintaining detection capabilities through alternative charge collection methods using channel stops and trench structures.
Solution Approach 2:
The patent segments the charge collection function by introducing channel stops and trench structures that divide the active area into regions for collecting signal charges and secondary charges separately. This segmentation allows efficient charge collection without requiring the thick substrate and high voltage previously needed.
2Reliability
If a thick substrate is used to enable detection of deeply penetrating radiation, then detection capability for deep penetration radiation is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent removes the conductive backside layer and the complex processing steps associated with creating and contacting it. This extraction of the problematic component directly reduces manufacturing complexity and cost while maintaining detection performance through the simplified structure.
3Reliability
If backside illumination is used to improve quantum efficiency for blue light, then quantum efficiency is improved, but image quality degrades due to long charge drift distance
Solution Approach 1:
The patent introduces vertical dimensionality through trench structures and channel stops that create three-dimensional charge collection regions. This allows efficient collection of signal charges generated by blue light absorption at the backside while minimizing drift distance through the structured geometry, thereby maintaining both quantum efficiency and image quality.
4Ease of operation
If a conductive backside layer is used to transport secondary charges outside the active area, then charge transport is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent removes the conductive backside layer entirely, extracting the component that was transporting secondary charges outside the active area. Secondary charges are now collected within the active area by channel stops and trench structures, simplifying the device while maintaining charge transport efficiency.
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 design enables efficient detection of visible light with reduced power consumption and manufacturing complexity, improving image quality and quantum efficiency for blue light while maintaining high sensitivity for deep penetration radiation.
Implementation Method 1
Radiation is converted to electron hole pairs in semiconductor material
Implementation Method 2
In semiconductor radiation detectors the electron hole pairs are separated by an electric field
Data Source
AI summary
A semiconductor radiation detector comprises a bulk layer of semiconductor material, and on a first surface of the bulk layer in the following order: a modified internal gate layer of semiconductor of second conductivity type, a barrier layer of semiconductor of first conductivity type and pixel dopings of semiconductor of the second conductivity type. The pixel dopings are adapted to be coupled to at least one pixel voltage in order to create pixels corresponding to pixel dopings. The device comprises a first conductivity type first contact. Said pixel voltage is defined as a potential difference between the pixel doping and the first contact. The bulk layer is of the first conductivity type. On a second surface of the bulk layer opposite to the first surface, there is nonconductive back side layer that would transport secondary charges outside the active area of the device or function as the radiation entry window.