Radiation Detection Element Doping Layout for Wider Charge Collection
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Solution Overview
Problem
Conventional radiation detection elements with semiconductor materials face challenges in efficiently collecting charges generated far from the first electrode due to gentle electric potential gradients, leading to reduced sensitive area and inaccurate signal processing.
Innovation Solution
A radiation detection element with a heavily-doped layer on the second surface, positioned to overlap with the second electrode and thicker than it, enhances the electric potential gradient, ensuring charges generated far from the first electrode are efficiently collected by creating an electric field directed towards the first electrode, thereby expanding the sensitive area without increasing the element's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a collimator is disposed to cover the region where the electric potential gradient is gentle, then charge collection accuracy is improved, but the device size increases
Solution Approach 1:
The invention changes the electrical parameters of the semiconductor substrate by forming a heavily-doped layer with high-concentration impurities. This modifies the electric potential distribution inside the substrate, creating a steeper potential gradient that directs charges toward the first electrode, thereby improving charge collection accuracy without adding physical collimator structures.
2Speed
If an electrode is disposed around the second electrode to increase the electric potential gradient, then charge collection speed is improved, but the structure becomes complicated and size increases
Solution Approach 1:
The invention applies local quality by creating a heavily-doped layer at specific regions of the semiconductor substrate. This localized modification of dopant concentration generates the required electric potential gradient in critical areas without requiring additional electrodes or complex wiring structures throughout the device.
Solution Approach 2:
The heavily-doped layer acts as a virtual electrode by generating an electric field that mimics the effect of a physical electrode. This 'electrical copying' of the electrode function is achieved through dopant distribution rather than physical structure, simplifying the device design.
3Volume of moving object
If the size of the radiation detection element is fixed, then device compactness is improved, but the sensitive area for detecting radiation is reduced
Solution Approach 1:
By changing the electrical parameters through heavy doping, the invention extends the effective collection range of the first electrode. The modified electric potential distribution allows charges generated over a larger area to be collected by the same electrode, effectively increasing the sensitive area without increasing the physical device size.
4Area of stationary object
If multiple first electrodes are arranged on one surface of the semiconductor, then charge collection coverage is improved, but signal obscuration occurs in intermediate regions
Solution Approach 1:
The heavily-doped layer creates a dominant electric potential gradient that directs charges toward the first electrode regardless of proximity to other electrodes. This parameter modification eliminates the ambiguity in intermediate regions, ensuring that charges from any location are collected by the intended electrode without signal obscuration.
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 solution effectively expands the sensitive area for radiation detection, improving detection efficiency by ensuring reliable collection of charges generated at positions far from the first electrode, while maintaining a simple structure and preventing signal obscuration from intermediate regions.
Implementation Method 1
By application of voltage, an electric field is generated inside the semiconductor part. If radiation is incident into the semiconductor part, electric charges are generated inside the semiconductor part and move in accordance with the electric field.
Implementation Method 2
a heavily-doped layer that is disposed at a region of the second surface excluding an edge of the semiconductor part and is doped heavier than the semiconductor part with dopants for making a type of a semiconductor equal to that of the semiconductor part
Data Source
AI summary
The radiation detection element comprising a semiconductor part having a plate shape, a first electrode that is disposed on a first surface being one surface of the semiconductor part and that collects charges generated by incidence of radiation in the semiconductor part, a second electrode that is disposed on a second surface being the other surface of the semiconductor part and that is applied with voltage needed for collecting the charges, and a heavily-doped layer that is disposed at a region of the second surface excluding an edge of the semiconductor part and is doped heavier than the semiconductor part with dopants for making a type of a semiconductor equal to that of the semiconductor part. The heavily-doped layer is on the second surface located at a position overlapped with the second electrode and is thicker than the second electrode.