CdTe Radiation Detector Electrode Insulation via Tellurium Oxide Layer
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Solution Overview
Problem
Radiation detection elements with closely spaced electrodes suffer from insulation failures, leading to leakage currents and decreased spatial resolution, which compromises the ability to produce high-definition images.
Innovation Solution
A radiation detection element with a substrate made of cadmium telluride or cadmium zinc telluride, featuring a thin tellurium oxide layer of 100 nm or less between electrode portions, and an insulating portion width of 100 μm or less, to prevent current leakage and enhance adhesion between electrodes and the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the distance between electrodes is reduced to achieve high-definition imaging, then measurement precision is improved, but insulation reliability deteriorates due to leakage currents
Solution Approach 1:
The patent applies local quality by creating a tellurium oxide layer with specific thickness characteristics at different locations. The layer is thinner (100 nm or less) at the end portions of insulating portions where electrodes are closely spaced, and thicker in intermediate regions. This localized thickness variation provides enhanced insulation exactly where leakage currents are most likely to occur between closely spaced electrodes, while maintaining overall insulating coverage.
Solution Approach 2:
The patent changes the physical parameter of the tellurium oxide layer thickness to resolve the contradiction. By controlling the layer thickness to be 100 nm or less at critical locations (end portions of insulating portions), the patent optimizes the balance between insulation performance and electrical contact. This parameter change allows electrodes to be spaced closer for high-definition imaging while preventing leakage currents through the optimized insulating structure.
2Strength
If an intermediate layer is formed to improve adhesion between electrode and substrate, then strength is improved, but insulation performance may deteriorate due to current leakage
Solution Approach 1:
The patent changes the thickness parameter of the tellurium oxide intermediate layer to simultaneously achieve adhesion and insulation. By controlling the thickness to be 100 nm or less at end portions of insulating portions, the layer provides sufficient adhesion between the electrode and CdTe substrate while being thin enough to prevent current leakage paths, thus resolving the contradiction between strength and insulation reliability.
Solution Approach 2:
The patent applies local quality by varying the tellurium oxide layer thickness across different regions. The layer is thinner at end portions of insulating portions where insulation is critical, and can be thicker in intermediate regions where adhesion is the primary concern. This spatial variation in layer properties allows the system to achieve both strong adhesion and reliable insulation 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
The solution ensures reliable insulation and prevents element performance defects, enabling high-definition imaging and reducing defective product rates by blocking current leakage paths, thus improving the yield and performance of radiation detection elements.
Implementation Method 1
an intermediate layer containing tellurium oxide is present between each of the electrode portions and the substrate, wherein the tellurium oxide layer has a thickness of 100 nm or less on a 500 nm inner side from an end portion of the insulating portion
Implementation Method 2
it is possible to electrically detect the radiation by applying a high bias voltage to an insulating CdTe-based crystal having a high resistivity, and converting incidence of the radiation into a current signal by a (internal) photoelectric effect generated when the radiation is incident upon the crystal material
Data Source
AI summary
Provided is a radiation detection element, including: a plurality of electrode portions on a surface of a substrate; and an insulating portion between the electrode portions, the substrate being made of a compound semiconductor crystal containing cadmium telluride or cadmium zinc telluride, wherein an intermediate layer containing tellurium oxide is present between each of the electrode portions and the substrate, and wherein the tellurium oxide layer has a thickness of 100 nm or less on a 500 nm inner side from an end portion of the insulating portion between the electrode portions. The radiation detection element has higher adhesion of the electrodes, and does not result in an element performance defect caused by insufficient insulation between the electrodes, even if the radiation detection element has a narrower distance between the electrode portions in order to obtain a high-definition radiographic image.