SOI Radiation Detector Cell With Stacked Diode-Transistor Layout
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ionizing radiation detectors face inefficiencies in detection sensitivity and surface area utilization, as they typically require separate locations for diodes and transistors, leading to reduced detection capabilities and increased chip space usage.
Innovation Solution
A device comprising a diode and a transistor connected in parallel, where the transistor is located on an electrically-insulating layer covering a PN junction, enhancing detection sensitivity by allowing ionizing radiation to generate current through the PN junction, which is then compared to a threshold voltage, thereby improving detection probability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate locations are used for diodes and transistors in traditional detectors, then device functionality is maintained, but detection sensitivity is reduced and chip surface area increases
Solution Approach 1:
The patent merges the diode and transistor into a single integrated device structure where the transistor is formed on an electrically-insulating layer covering the PN junction of the diode. This combination allows the device to function as both a radiation detector and a signal processing element, achieving over 100 to 500 times higher detection sensitivity while reducing the required chip surface area compared to traditional separate implementations.
Solution Approach 2:
The patent utilizes vertical stacking in the SOI structure, placing the transistor on top of the insulating layer that covers the PN junction. This three-dimensional integration approach allows both components to occupy different vertical layers rather than requiring separate horizontal space, thereby increasing detection sensitivity without proportionally increasing chip surface area.
2Measurement precision
If separate locations are used for diodes and transistors in traditional detectors, then device functionality is maintained, but chip surface area increases
Solution Approach 1:
The patent combines the diode and transistor into a single integrated device where the transistor is formed on an electrically-insulating layer covering the PN junction. This merger maintains full functionality of both components while achieving over 100 to 500 times higher detection sensitivity and reducing chip surface area requirements.
3Area of stationary object
If a compact integrated structure is used, then chip surface area is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent employs specific parameter choices in the SOI structure, including the electrical-insulating layer thickness (ranging from 1 nm to 10 μm) and doping concentrations, to optimize both the compact integration and manufacturability. These parameter adjustments enable the compact structure to be fabricated using standard 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 solution significantly increases detection sensitivity, with the device being more than 100 to 500 times more sensitive than traditional designs, while also reducing chip surface area usage by integrating the diode and transistor in a compact SOI-type structure.
Implementation Method 1
Ionizing radiations are generally formed of, or originate from, high-energy particles, that is, particles having an energy greater than a few eV, for example, greater than approximately 13 eV, most often greater than 1 keV, or even greater than 1 MeV
Implementation Method 2
the generation of a current through the PN junction by the ionizing radiation
Data Source
AI summary
A diode and a transistor are connected in parallel. The transistor is located on a first doped region forming a PN junction of the diode with a second doped region located under the first region. The circuit functions as an ionizing radiation detection cell by generating a current through the PN junction which changes by a voltage generated across the transistor. This change in voltage is compared to a threshold to detect the ionizing radiation.