Ion-Sensitive Sensor Layer Structure for Stability
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Solution Overview
Problem
Ion-sensitive sensors with EIS structures face challenges in achieving long-term chemical and electrical stability, leading to inadequate measurement accuracy and high manufacturing costs, which limits their introduction in industrial process monitoring and environmental applications.
Innovation Solution
A method for manufacturing an ion-sensitive sensor structure involving a semiconductor substrate with a metal oxide layer and a metal layer, where the metal oxide layer acts as a buffer, deposited and thermally treated to create a crystallized and oxidized layer sequence, preventing damage to the oxide layer and reducing residual interface charges, thereby enhancing stability and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional glass electrodes are used for ion concentration measurement, then measurement capability is achieved, but miniaturization is limited due to requirements for large inner buffer volume and stable glass membrane
Solution Approach 1:
The patent replaces the mechanical glass membrane structure with an EIS (Electrolyte-Insulator-Semiconductor) structure consisting of a semiconductor substrate, insulator layer, and electrolyte contact layer. This substitution enables miniaturization while maintaining measurement stability, as the EIS structure can be fabricated using standard semiconductor processes and does not require the bulky glass membrane and large buffer volume of conventional electrodes.
Solution Approach 2:
The patent optimizes the thickness parameters of the insulator layer (50-200 nm) and electrolyte contact layer (10-50 nm) to achieve both miniaturization and stable measurement. By precisely controlling these layer thicknesses during fabrication, the sensor achieves high measurement stability in a miniaturized form factor.
2Measurement precision
If glass electrodes are used for pH measurement, then measurement capability is achieved, but high impedance results due to glass membrane thickness, causing sensitivity to electrical environmental disturbances
Solution Approach 1:
The patent replaces the high-impedance glass membrane with an EIS structure that provides low output impedance. The semiconductor substrate and insulator layer combination creates a field-effect transistor-like structure that converts the high-impedance ion concentration signal into a low-impedance electrical signal, making the sensor insensitive to electrical environmental disturbances while maintaining pH measurement accuracy.
3Reliability
If glass electrodes are used for ion measurement, then measurement capability is achieved, but glass breakage risk exists under certain conditions, limiting use in fields like food technology
Solution Approach 1:
The patent replaces the fragile glass membrane with a robust EIS structure fabricated from semiconductor materials. The insulator layer (such as silicon dioxide) and semiconductor substrate provide mechanical strength and chemical stability without the breakage risk of glass, enabling use in demanding environments like food technology where sterilization and mechanical durability are required.
Solution Approach 2:
The patent uses composite material structures combining semiconductor substrate, insulator layers, and electrolyte contact layers to achieve both mechanical robustness and chemical stability. This composite approach eliminates glass while maintaining the necessary measurement stability and enabling harsh environment operation.
4Volume of moving object
If ion-sensitive EIS structures are used for ion concentration measurement, then miniaturization and avoidance of glass breakage are achieved, but chemical and electrical long term stability is insufficient, making sensors complex and expensive to manufacture
Solution Approach 1:
The patent designs the EIS structure to serve multiple functions simultaneously: the insulator layer provides both electrical isolation and chemical stability, the semiconductor substrate provides both mechanical support and electrical activity, and the electrolyte contact layer provides both ion access and protective coating. This multi-functionality reduces the need for additional components, simplifying manufacturing while maintaining miniaturization and long-term stability.
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 approach results in increased stability, sensitivity, and minimal drift for ion-sensitive sensors, allowing for precise and reproducible measurements, and reduces the risk of glass breakage, enabling their use in industrial and environmental monitoring.
Implementation Method 1
a metal oxide layer and a metal layer have been deposited and tempered, in order to obtain a layer sequence, respectively double layer (or a plurality of double layers), having a crystallized metal oxide layer and an oxidized and crystallized metal layer
Implementation Method 2
a metal oxide layer and a metal layer have been deposited and tempered, in order to obtain a layer sequence, respectively double layer (or a plurality of double layers), having a crystallized metal oxide layer and an oxidized and crystallized metal layer
Implementation Method 3
the metal layer is then subjected to a thermal treatment in order to obtain a thermally oxidized and crystallized metal layer
Data Source
AI summary
In a method for manufacturing an ion-sensitive structure for an ion-sensitive sensor, first a semiconductor substrate bearing an oxide layer is provided, whereupon a metal oxide layer and a metal layer are deposited and tempered, in order to obtain a layer sequence having a crystallized metal oxide layer and an oxidized and crystallized metal layer on the semiconductor substrate bearing the oxide layer. In such case, the metal oxide layer and the metal layer have a compatible metal element, and the coating thickness dMOX of the metal oxide layer is greater than the coating thickness dMET of the metal layer.