Radiation Detector Element With Barrier Layer For Low Resistance
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Solution Overview
Problem
Radiation detector elements with high resistance to current passage lead to depolarization issues, especially when multiple elements share a common electric contact, reducing the performance and accuracy of radiation detection systems.
Innovation Solution
A radiation detector element comprising a stack of layers with a radiation-absorbing semiconductor material and a barrier layer, along with a reading circuit, where the absorbing layer has p-n junctions and a barrier layer with a higher band gap value, and a conducting zone with a high free carrier density, reducing electrical resistance and optimizing radiation detection without the need for a metal layer that absorbs radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal layer is placed on the surface of the absorbing layer to electrically connect the second portion to the reading circuit, then the electrical resistance is reduced, but the metal layer absorbs part of the radiation to be detected, reducing detection performance
Solution Approach 1:
The patent introduces an intermediary material (semiconductor material with higher band gap) between the absorbing layer and the reading circuit to provide electrical connection without absorbing the detected radiation. This intermediary layer serves as a mediator that fulfills the electrical connection function while being transparent to the radiation being detected.
Solution Approach 2:
The patent changes the material parameter (band gap energy) of the layer providing electrical connection. By selecting a semiconductor material with a higher band gap than the absorbing layer, the material becomes transparent to the radiation being detected while maintaining electrical conductivity through appropriate doping.
2Measurement precision
If the distance between the detector element and the electric contact is increased, then the detector element can be positioned optimally for radiation detection, but the electrical resistance increases due to depolarization
Solution Approach 1:
The patent uses an intermediary highly doped semiconductor layer to provide a low-resistance electrical path between the absorbing layer and the reading circuit. This intermediary structure allows the detector element to be optimally positioned for radiation detection while maintaining low electrical resistance through the doped semiconductor pathway.
3Reliability
If the doping concentration in the absorbing layer is increased to reduce electrical resistance, then the electrical connection is improved, but the radiation absorption efficiency may be affected
Solution Approach 1:
The patent applies different doping concentrations to different regions of the semiconductor structure. The absorbing layer maintains optimal low doping for radiation detection efficiency, while separate highly doped regions provide electrical connection pathways. This local differentiation of material properties allows simultaneous optimization of both radiation detection and electrical conductivity.
Solution Approach 2:
The patent segments the semiconductor structure into functionally distinct regions: a lightly doped absorbing layer for radiation detection and highly doped contact regions for electrical connection. This segmentation allows each region to be optimized for its specific function without compromising the other.
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 enhances the performance of radiation detector elements by reducing electrical resistance and minimizing radiation absorption losses, leading to improved detection accuracy and efficiency across the detector array.
Implementation Method 1
at least one barrier layer consisting of a second semiconductor material having a second band gap value, the second band gap value being strictly greater than the first band gap value
Implementation Method 2
When a photon is absorbed, it generates an electron-hole pair in the absorbing layer. The electrical field exerts a force on the electron and the hole that separates the electron-hole pair, and leads to an electric current.
Implementation Method 3
The p/n junction generates an electrical field in the absorbing layer
Implementation Method 4
a band being made from the second semiconductor material and having a doping of the first type and a free carrier density greater than or equal to 1×10^17 cm^-3
Data Source
AI summary
The invention relates to a radiation detector element (10) comprising a stack (15) of layers superimposed in a stacking direction (Z), the stack (15) having a first face (25) and a second face (30) and comprising a radiation-absorbing layer (35) consisting of a first semiconductor material (M1) having a first band gap value and at least one barrier layer (40) consisting of a second semiconductor material (M2) having a second band gap value, the second band gap value being strictly higher than the first band gap value. The second face (30) has at least one strip (105) defined in the stacking direction (Z) by the barrier layer (40), the strip (105) consisting of the second semiconductor material (M2) and having a doping of the first type and a free carrier density higher than or equal to 1.1017 cm−3.