Radiation Detection Element Conductive Layer Noise Reduction
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Solution Overview
Problem
Conventional radiation detection elements using semiconductors face challenges in controlling positive charges in insulating films, leading to noise due to unwanted electric charges generated in depleted regions, which affect the accuracy of radiation detection.
Innovation Solution
Incorporating a conductive layer with lower resistance than the semiconductor part but higher than the collection electrode, positioned between the semiconductor and insulating film, to facilitate the collection of electric charges not derived from radiation, thereby reducing noise by preventing their flow into the semiconductor part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conductive layer is added between the semiconductor part and insulating film to collect electric charges, then noise is reduced, but device complexity increases
Solution Approach 1:
A conductive layer with intermediate resistance (lower than semiconductor, higher than collection electrode) is inserted between the semiconductor part and insulating film. This intermediary layer facilitates the collection of electric charges not derived from radiation by providing a preferred conduction path to the collection electrode, thereby reducing noise without requiring fundamental structural redesign.
2Measurement precision
If the amount of positive charges in insulating film is increased to suppress charge generation, then noise is reduced, but manufacturing precision deteriorates
Solution Approach 1:
The conductive layer acts as an intermediary that provides a controlled conduction path for electric charges. Instead of relying on precise control of positive charges in the insulating film (which is difficult to manufacture), the conductive layer with its specific resistance characteristics passively guides charges to the collection electrode, achieving noise reduction through a more manufacturable parameter (resistance ratio).
3Productivity
If voltage is applied to generate electric field for charge collection, then charge collection efficiency is improved, but unwanted charge generation increases
Solution Approach 1:
The conductive layer is positioned specifically at the interface region where unwanted charges are generated (between semiconductor and insulating film). By providing a localized conduction path at this critical interface, the structure enables efficient collection of unwanted charges without requiring high voltage across the entire device, thereby reducing the generation of additional unwanted charges.
Solution Approach 2:
The conductive layer with intermediate resistance serves as a mediator that facilitates charge collection with reduced voltage requirements. The resistance matching between the conductive layer and adjacent materials creates an optimal conduction path that enhances charge collection efficiency without the need for high electric fields that would generate more unwanted charges.
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 effectively reduces noise in radiation detection elements, allowing for more precise detection of radiation by preventing irrelevant currents from entering the semiconductor part.
Implementation Method 1
the conductive layer being located at a position where a distance from the signal output electrode is equal to or longer than a distance between the collection electrode and the signal output electrode
Implementation Method 2
a potential gradient generation electrode for applying voltage such that a potential gradient in which a potential varies toward the signal output electrode is generated in the semiconductor part
Data Source
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AI summary
Provided are a radiation detection element, a radiation detector and a radiation detection apparatus that are able to reduce noise. A radiation detection element (1) comprises: a semiconductor part (11) generating an electric charge by entrance of radiation; a signal output electrode (14) provided at the semiconductor part (11) and outputting a signal caused by the electric charge; a potential gradient generation electrode (12) provided at the semiconductor part (11), for applying voltage such that a potential gradient in which a potential varies toward the signal output electrode (14) is generated inside the semiconductor part (11); a collection electrode (13) provided at the semiconductor part (11), for collecting electric charges not derived from radiation; an insulating film (15) provided on a side of the semiconductor part (11) where the signal output electrode (14) is located; and a conductive layer (17) provided between the insulating film (15) and a part of the semiconductor part (11), and having electric resistance lower than the electric resistance of the semiconductor part (11) and higher than the electric resistance of the collection electrode (13). The conductive layer (17) is located at a position where a distance from the signal output electrode (14) is equal to or longer than a distance between the collection electrode (13) and the signal output electrode (14).