Oxide Semiconductor Transistor X-ray Detector Off-Current Reduction
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Solution Overview
Problem
X-ray detectors using amorphous silicon channels have high off-current, leading to charge leakage and reduced image information transmission speed, while polysilicon channels have complex manufacturing processes and high costs.
Innovation Solution
An X-ray detector design incorporating an oxide semiconductor transistor with a channel made of materials like ZnO or SnO2, paired with a signal storage capacitor and a photoconductor, utilizing diffusion-prevention layers to minimize charge leakage and improve image reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If amorphous silicon channel is used in transistor, then manufacturing process is simple, but off-current is high causing charge leakage
Solution Approach 1:
The patent changes the material parameter of the transistor channel from amorphous silicon to oxide semiconductor, which fundamentally alters the electrical properties to achieve ultra-low off-current while maintaining manufacturing compatibility through similar thin-film deposition processes
Solution Approach 2:
The patent employs composite material structure by combining oxide semiconductor channel with specific gate insulator materials (such as silicon oxide or silicon nitride) to create a transistor that achieves both low off-current and reliable charge storage functionality
2Ease of manufacture
If amorphous silicon channel is used in transistor, then manufacturing cost is low, but charge mobility is low reducing information transmission speed
Solution Approach 1:
The patent changes the charge mobility parameter by substituting the channel material with oxide semiconductor, which exhibits significantly higher charge mobility than amorphous silicon, thereby increasing information transmission speed while keeping manufacturing costs competitive
3Speed
If polysilicon channel is used in transistor, then charge mobility is increased, but off-current is high and manufacturing complexity increases
Solution Approach 1:
The patent changes the material state parameter from crystalline polysilicon to amorphous oxide semiconductor, achieving high charge mobility through superior material properties while avoiding the complex crystallization processes and high-temperature treatments required for polysilicon
Solution Approach 2:
The patent replaces the mechanical/thermal processing steps required for polysilicon crystallization with vapor-phase deposition or sputtering processes for oxide semiconductor, eliminating complex manufacturing steps while achieving better electrical performance
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 oxide semiconductor transistor reduces off-current, enhances image reliability, and increases aperture ratio, resulting in improved sensitivity and reduced detector size.
Implementation Method 1
X-rays are converted directly into electric charges by a photoconductor
Implementation Method 2
the oxide semiconductor transistor reduces off-current, enhances image reliability
Data Source
AI summary
Example embodiments are directed an X-ray detector including an oxide semiconductor transistor. The X-ray detector including the oxide semiconductor transistor includes an oxide semiconductor transistor and a signal storage capacitor in parallel to each other on a substrate. The oxide semiconductor transistor includes a channel formed of an oxide semiconductor material, and a photoconductor. A pixel electrode and a common electrode are formed on opposite surfaces of the photoconductor. The channel includes ZnO, or a compound including ZnO and at least one selected from a group consisting of gallium (Ga), indium (In), hafnium (Hf), and tin (Sn).