Semiconductor Radiation Detector With Sidewall Passivation
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Solution Overview
Problem
Semiconductor radiation detectors face challenges in achieving improved radiation detection performance due to physical size constraints, leakage currents, and inefficient radiation entrance windows, which compromise detection efficiency.
Innovation Solution
The implementation of a semiconductor radiation detector design featuring a semiconductor block with a radiation entrance window and layers inducing an electric field to passivate side surfaces, reducing leakage currents and enhancing detection performance by using a negatively charged dielectric layer as the radiation entrance window, which creates an induced junction to repel electrons and improve signal collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the physical size of the semiconductor radiation detector is reduced, then the detector can be positioned closer to the radiation source and requires less material, but the detection efficiency and radiation capture capability are compromised
Solution Approach 1:
The patent applies local quality by creating a non-uniform electric field distribution within the semiconductor block. The electric field strength is optimized locally in different regions: stronger near the radiation entrance window to efficiently collect charge carriers generated by incident radiation, and gradually decreasing towards the exit window. This localized field optimization allows the detector to maintain high detection efficiency in a compact volume by concentrating the electric field where it is most needed for radiation interaction and charge collection.
2Measurement precision
If high electric potential is applied to field electrodes to create sufficient electric field for charge collection, then signal charge collection is improved, but leakage current increases compromising detection performance
Solution Approach 1:
The patent employs parameter changes by optimizing the electric potential distribution across the semiconductor block. Instead of applying uniform high potential, the invention uses a graded potential approach where the electric field strength varies spatially. The potential is highest near the radiation entrance window to ensure efficient charge collection from radiation interactions, then gradually decreases through the bulk material. This parameter optimization allows sufficient electric field for signal collection while keeping the maximum potential (and thus leakage current) at acceptable levels.
Solution Approach 2:
The patent introduces an intermediary approach by using the semiconductor material itself as the medium that distributes and modulates the electric field. The intrinsic properties of the semiconductor (such as carrier mobility and recombination characteristics) act as intermediaries that allow efficient charge collection at lower applied potentials compared to vacuum or gas-based detectors. The material's electronic structure mediates between the applied electric field and the charge carriers, enabling effective signal collection with reduced leakage current.
3Object-generated harmful factors
If guard electrodes are added to passivate the semiconductor block perimeter and reduce leakage currents, then leakage current is reduced, but the device complexity and structural sophistication increase
Solution Approach 1:
The patent applies merging by integrating the field electrodes and guard electrodes into a single unified electrode structure. Rather than treating them as separate components requiring independent control, the invention designs them as a continuous or closely coupled electrode arrangement that simultaneously performs both field generation and perimeter passivation functions. This merged structure reduces the number of independent control circuits and simplifies the overall device architecture while maintaining effective leakage current suppression.
Solution Approach 2:
The patent implements multi-functionality by designing the electrode arrangement to serve multiple purposes: the same electrode structure that generates the primary electric field for charge collection also acts as a guard electrode to passivate the semiconductor perimeter and suppress leakage currents. This universal electrode design eliminates the need for dedicated guard electrodes in many configurations, reducing device complexity while achieving both signal collection and leakage reduction objectives simultaneously.
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 allows for improved radiation detection performance by minimizing leakage currents and optimizing the use of detector surface area, enabling more effective capture of incident radiation while reducing the detector's physical size without compromising detection efficiency.
Implementation Method 1
an arrangement of one or more layers having a net charge arranged to substantially cover at least one side surface of the semiconductor block to induce an electric field for passivating the at least one side surface
Implementation Method 2
the electrode arrangement is arranged to generate an electric field within the semiconductor block for driving charge carriers generated therein due to incident radiation towards the at least one collector electrode
Implementation Method 3
using a negatively charged dielectric layer as the radiation entrance window, which creates an induced junction to repel electrons and improve signal collection
Data Source
AI summary
A semiconductor radiation detector includes: a semiconductor block of a first conductivity type and including majority charge carriers of a first polarity; an electrode embedded on a surface of the semiconductor block, the electrode including a collector embedded on a front surface of the semiconductor block and further electrodes arranged to generate an electric field within the semiconductor block for driving charge carriers of the first polarity generated therein due to incident radiation towards the collector; a radiation entrance window receiving the incident radiation, arranged to cover at least portion of a back surface of the semiconductor block opposite its front surface; and layers having a net charge of the first polarity and substantially covering at least one side surface of the semiconductor block to induce an electric field for passivating the at least one side surface of the semiconductor block so as to reduce leakage currents arising therein.