Epitaxial X-ray Detector Bonded to Electronics Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor X-ray detectors face challenges in heat management, making it difficult to produce large-area detectors with a large number of pixels, and scintillators trade off spatial resolution for absorption efficiency.
Innovation Solution
The development of an X-ray detector comprising an epitaxial layer with a p-n or p-i-n junction, bonded to an electronics layer with a scintillator layer, which includes porous silicon, and a common electrode, allowing for efficient detection of X-ray fluorescence through electrical signals generated in the epitaxial layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If scintillator thickness is increased to improve absorption efficiency, then absorption efficiency is improved, but spatial resolution deteriorates
Solution Approach 1:
The patent introduces an X-ray absorbing layer with high atomic number material (e.g., cadmium telluride, mercury iodide) as an intermediary between the X-ray source and scintillator. This layer pre-absorbs X-rays and converts them to visible light, reducing the X-ray flux reaching the scintillator. Consequently, the scintillator can be made thinner to maintain spatial resolution while still achieving high overall absorption efficiency through the combined action of the X-ray absorbing layer and scintillator.
2Productivity
If semiconductor detector area and pixel number are increased, then detection capability is improved, but heat management becomes difficult
Solution Approach 1:
The patent divides the detector into multiple independent pixel regions with individual readout circuits. Each pixel or small group of pixels has its own signal processing capability, allowing for localized heat dissipation and reduced thermal interference between adjacent detection elements. This segmentation enables large-area detectors with high pixel counts while maintaining manageable thermal characteristics through distributed heat management.
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 solution enables effective detection of X-ray fluorescence with improved spatial resolution and absorption efficiency, overcoming the heat management issues in semiconductor detectors and scintillator limitations.
Implementation Method 1
When an X-ray photon is absorbed in the semiconductor layer, multiple charge carriers (e.g., electrons and holes) are generated
Implementation Method 2
multiple charge carriers (e.g., electrons and holes) are generated and swept under an electric field towards electrical contacts on the semiconductor layer
Implementation Method 3
scintillators (e.g., sodium iodide) absorb X-ray and emit visible light
Implementation Method 4
bonded to an electronics layer with a scintillator layer, which includes porous silicon
Data Source
AI summary
Disclosed herein is a method comprising: forming electrical contacts on a first surface of an epitaxial layer supported on a substrate, the first surface being opposite from the substrate; bonding the epitaxial layer to an electronics layer, wherein the first surface faces the electronics layer and the electrical contacts on the first surface are bonded to electrical contacts of the electronics layer; exposing a second surface opposite the first surface by removing the substrate; and forming a common electrode on the second surface.