Amorphous Oxide FET for Flexible X-Ray Detection
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Solution Overview
Problem
Current sensors for detecting ionizing radiation, such as X-rays, face challenges in achieving high sensitivity, low power consumption, flexible mechanical properties, and cost-effective mass production, while also providing real-time electronic readout and high bandwidth, particularly in wearable devices.
Innovation Solution
A high mobility amorphous oxide semiconductor field effect transistor with a multilayer dielectric oxide structure on a flexible substrate, featuring a high-Z main layer and insulating layers, which increases X-ray photon absorption and sensitivity, allowing for real-time detection and monitoring of ionizing radiation with low leakage current and minimal power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If CMOS technology is used for RFID sensors, then mass production and low cost are achieved, but leakage current increases power consumption
Solution Approach 1:
The patent changes the material parameter from conventional CMOS semiconductor to amorphous oxide semiconductor, which fundamentally alters the electrical characteristics to achieve ultra-low leakage current while remaining compatible with existing manufacturing processes. This material substitution enables sensors to operate with picowatt-level power consumption without requiring complete process redesign.
Solution Approach 2:
The patent employs a composite structure combining amorphous oxide semiconductor channel layer with high-k dielectric materials (such as hafnium oxide or aluminum oxide) for the gate insulator. This composite approach leverages the high mobility and low leakage of oxide semiconductors while using high-k materials to enhance gate control efficiency, achieving both low power consumption and high sensitivity.
2Measurement precision
If high-Z dielectric layer is added to increase X-ray absorption, then sensitivity improves, but device complexity increases
Solution Approach 1:
The high-Z dielectric layer serves multiple functions simultaneously: it acts as the gate insulator providing electrical isolation, serves as the X-ray absorption layer for sensing, and functions as part of the overall device structure. This multi-functionality eliminates the need for separate absorption layers, reducing overall device complexity while maintaining high sensitivity.
Solution Approach 2:
The patent applies the high-Z dielectric material specifically in the gate insulator region where it is most needed for both electrical isolation and X-ray absorption. The material composition and thickness are optimized locally to achieve maximum X-ray attenuation while maintaining appropriate electrical properties for transistor operation.
3Use of energy by moving object
If amorphous oxide semiconductor is used to reduce leakage current, then power consumption decreases, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs sputtering deposition with intentionally designed short-lived amorphous phases that are subsequently crystallized or stabilized. This approach uses relatively simple, cost-effective sputtering equipment and processes rather than requiring complex molecular beam epitaxy or atomic layer deposition systems, making the technology accessible for mass production despite the precision requirements.
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 device achieves high sensitivity and real-time detection of ionizing radiation with low power consumption, maintaining impedance variation post-sensing event, and is suitable for flexible, low-cost mass production, enabling effective dosimetry and wearable radiation detection.
Implementation Method 1
feature a high-Z main layer and insulating layers, which increases X-ray photon absorption and sensitivity
Implementation Method 2
A high mobility amorphous oxide semiconductor field effect transistor with low leakage current and minimal power consumption
Data Source
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Figure 3(a)~3(c)
AI summary
The present invention concerns a sensitive field effect device (100) comprising a semiconductor channel (110), a source electrode (120) connected to said semiconductor channel (110), a drain electrode (130) connected to said semiconductor channel (110), such that said semiconductor channel (110) is interposed between said source electrode (120) and said drain electrode (130), a gate electrode (140) and a dielectric layer (150) interposed between said gate electrode (140) and said semiconductor channel (110), characterized in that said semiconductor channel (110) is a layer and is made of an amorphous oxide and in that said sensor means (170, 171, 172, 173, 174, 175, 175) are configured to change the voltage between said gate electrode (140) and said source electrode (120) upon a sensing event capable of changing their electrical state. The present invention also concerns a sensor and a method for manufacturing said field effect device (100).