Integrated X-ray Detector with Direct Absorber Integration
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Solution Overview
Problem
Current X-ray detector technologies, particularly in CT scanners, face limitations such as inability to perform X-ray photon counting, low spatial resolution, and material brittleness, which restrict high-temperature assembly and integration density due to the use of materials like CdTe or CdZnTe.
Innovation Solution
The integration of direct detection elements onto the backend of a readout integrated circuit without wire bonds or bumps, allowing high-temperature assembly and using materials like metal halide perovskites or Thallium halides for efficient X-ray detection with fast response times, enabling photon counting and improved spatial resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct detectors based on CdTe or CdZnTe are used, then X-ray photon detection capability is improved, but material brittleness and susceptibility to thermal shock worsen, limiting integration flexibility and requiring low temperature assembly
Solution Approach 1:
The patent changes the material parameters by selecting absorber materials (CdTe, CdZnTe, or perovskites) with appropriate bandgaps for X-ray detection while accepting their brittleness, and compensates through process parameter changes by implementing low-temperature assembly procedures and optimized device structures that reduce mechanical stress on the fragile absorber layers
Solution Approach 2:
The patent employs composite material structures where fragile absorber layers (CdTe/CdZnTe/perovskites) are integrated with robust support structures including buffer layers, adhesion layers, and flexible substrate configurations that provide mechanical strength while maintaining the detection functionality of the absorber materials
2Reliability
If wire bonds or bumps are used to connect direct detection elements to readout circuit, then electrical connection is achieved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges the absorber layer fabrication with the readout circuit fabrication into a single integrated device structure, eliminating the need for separate wire bonding or bump attachment steps. The absorber is deposited directly onto the readout circuit substrate, creating a monolithic integration that simplifies manufacturing while ensuring reliable electrical connections through direct contact
3Ease of manufacture
If conventional silicon photodiodes with scintillators are used, then manufacturing is easier, but X-ray photon counting capability and spatial resolution are lost
Solution Approach 1:
The patent extracts and eliminates the scintillator conversion step from the conventional detection architecture, using direct detection absorber materials that convert X-rays directly to electrical signals. This removes the intermediate visible light conversion process, enabling photon counting capability and superior spatial resolution while maintaining manufacturing feasibility through direct deposition techniques
4Speed
If absorber materials with fast response times are used, then photon counting capability is enabled, but material selection and integration flexibility are reduced
Solution Approach 1:
The patent establishes a universal device architecture and low-temperature assembly platform that can accommodate multiple absorber material types (CdTe, CdZnTe, perovskites) with different response times and bandgaps. This multi-functional platform allows selection of materials based on specific application requirements while maintaining consistent manufacturing processes and device integration methods
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 approach enables fast and efficient direct detection of X-ray photons with response times under 100 nanoseconds, overcoming material limitations and allowing for high-temperature assembly, thus enhancing detector performance and flexibility.
Implementation Method 1
an absorber portion is arranged on the contact surface of the dielectric portion, wherein the absorber portion comprises an absorber element that is in electrical contact with the metal structure. The absorber element is configured to absorb X-ray photons and generate electrical charges based on the absorbed X-ray photons
Data Source
AI summary
An integrated detector device for direct detection of X-ray photons includes a CMOS body including a substrate portion and a dielectric portion arranged on a main surface of the substrate portion, an integrated circuit in the CMOS body having implants at or above the main surface for forming charge collectors, and a metal structure in the dielectric portion that extends from the charge collectors to a contact surface of the dielectric portion facing away from the substrate portion. The device further includes an absorber portion arranged on the contact surface of the dielectric portion, the absorber portion including an absorber element that is in electrical contact with the metal structure, and an electrode structure that is in direct contact with the absorber element forming an electrical contact. The absorber element is configured to absorb X-ray photons and generate electrical charges based on the absorbed X-ray photons.