Soft X-ray Detection Shielding for Amplifier Protection
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Solution Overview
Problem
Existing soft X-ray detection apparatuses face challenges in accurately measuring soft X-ray energy due to the discharge of generated electric charge to regions other than detection nodes, leading to incomplete signal readout and inaccurate energy measurement, particularly when the detection unit includes an amplifier unit.
Innovation Solution
A shielding structure is implemented above the circuit unit of the semiconductor substrate, using materials with high atomic numbers like tantalum to block soft X-rays from incident on the amplifier transistor, ensuring that almost all generated electric charge can be collected and read accurately, thereby enhancing the accuracy of energy measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a detection unit includes an amplifier unit to amplify signals from the conversion unit, then signal amplification capability is improved, but the risk of soft X-ray radiation reaching the amplifier unit and causing inaccurate readings increases
Solution Approach 1:
The semiconductor substrate is divided into distinct functional regions: a conversion unit region for photon-to-electron conversion and a circuit unit region containing the amplifier unit. This spatial segmentation allows the amplifier to be positioned away from direct soft X-ray exposure while maintaining signal amplification capability.
Solution Approach 2:
A shielding unit made of high-atomic-number material (such as tungsten or gold) is introduced as an intermediary between the soft X-ray source and the circuit unit. This shielding unit absorbs or blocks soft X-ray radiation before it can reach the amplifier unit, preventing harmful interference while allowing the amplifier to function correctly.
2Device complexity
If the detection unit structure is simplified without a shielding unit, then device complexity is reduced, but measurement precision deteriorates due to charge discharge to regions other than detection nodes
Solution Approach 1:
The semiconductor substrate is divided into distinct functional regions: a conversion unit region for photon-to-electron conversion and a circuit unit region containing the amplifier unit. This spatial segmentation allows the amplifier to be positioned away from direct soft X-ray exposure while maintaining signal amplification capability.
Solution Approach 2:
A shielding unit made of high-atomic-number material (such as tungsten or gold) is introduced as an intermediary between the soft X-ray source and the circuit unit. This shielding unit absorbs or blocks soft X-ray radiation before it can reach the amplifier unit, preventing harmful interference while allowing the amplifier to function correctly.
3Object-affected harmful factors
If high-atomic-number materials are used for the shielding unit, then soft X-ray blocking capability is improved, but manufacturing complexity increases
Solution Approach 1:
The shielding unit is formed using high-atomic-number materials such as tungsten or gold, which have superior soft X-ray absorption coefficients. These materials provide effective shielding with thinner layers compared to low-atomic-number materials, reducing overall device thickness while maintaining blocking capability.
Solution Approach 2:
The atomic number of the shielding material is optimized to balance shielding effectiveness with manufacturability. By selecting materials with appropriate atomic numbers (higher than standard semiconductor materials but manageable for fabrication), the patent achieves effective soft X-ray blocking while maintaining compatibility with existing semiconductor manufacturing processes.
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 proposed solution significantly increases the percentage of output signals that accurately indicate the energy of incident soft X-rays, improving the detection accuracy and reliability of soft X-ray measurements by preventing unwanted soft X-ray radiation from reaching the circuit unit.
Implementation Method 1
a shielding unit 7 that blocks a soft X-ray which can be incident on the circuit unit 4
Implementation Method 2
a conversion unit 3 and a circuit unit 4 disposed on the semiconductor substrate 2. The conversion unit 3 has a conversion element, such as a photodiode, disposed therein
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A soft X-ray detection apparatus includes a semiconductor substrate (2) having a conversion unit (3) and a circuit unit (4) disposed therein. The conversion unit (3) is formed from, for example, a photodiode and collects electric charge generated upon incidence of a soft X-ray. The circuit unit (4) includes an amplifier transistor (6). The amplifier transistor (6) serves as an amplifier unit that amplifies and outputs a signal supplied from the conversion unit (3). A shielding unit (7) is disposed above the circuit unit (4). The shielding unit (7) blocks the soft X-ray incident on the circuit unit (4). The soft X-ray shielding coefficient of a material that forms the shielding unit (7) is higher than the soft X-ray shielding coefficient of each of aluminum and copper. Alternatively, the material of the shielding unit (7) is configured from an element having an atomic number higher than or equal to 70.