FET Metal Ion Detection in Extreme pH Solutions
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Solution Overview
Problem
Existing methods for detecting low-concentration metal ions in semiconductor manufacturing solutions, particularly in high acidity, alkalinity, or organic solutions, are limited by detection sensitivity, non-specific adsorption, and the absence of effective quantitative methods, leading to production defects and high costs.
Innovation Solution
A detection method using field effect transistors (FETs) with pH adjustment and gate biasing to measure electronic signals, employing a control solution for calibration, and functional groups to attract specific ions and resist non-specific adsorption, allowing for rapid and cost-effective concentration inference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ICP-MS or AA is used for metal ion detection, then detection sensitivity reaches ppt level, but the cost and operational complexity increase significantly
Solution Approach 1:
The patent uses a simple FET sensor that can be easily fabricated and replaced, avoiding the need for expensive, complex ICP-MS or AA instruments. The sensor is designed to be cost-effective and suitable for routine monitoring applications where high sensitivity is needed but instrument complexity must be minimized.
Solution Approach 2:
The patent replaces complex mechanical/optical detection systems (ICP-MS, AA) with an electronic field-effect transistor-based sensing system. This substitution uses electrical field effects rather than complex optical paths or mass spectrometry mechanisms, thereby reducing device complexity while maintaining detection capability.
2Adaptability or versatility
If FET is used for metal ion detection in extreme pH solutions, then detection capability is improved, but the FET is damaged by strong acids and strong alkalis
Solution Approach 1:
The patent introduces a gate oxide layer as an intermediary protective barrier between the FET and the extreme pH solution. This gate oxide acts as a mediator that protects the sensitive FET structure from direct exposure to damaging strong acids and alkalis, enabling the sensor to operate reliably in extreme pH conditions while maintaining detection capability.
3Object-affected harmful factors
If dilution is used to reduce pH influence, then pH interference is reduced, but detection of already low-concentration metal ions becomes more difficult
Solution Approach 1:
The gate oxide layer serves as a mediator that allows the FET to withstand extreme pH conditions without requiring dilution of the sample. This enables direct measurement of metal ions in concentrated extreme pH solutions, maintaining both pH tolerance and detection sensitivity simultaneously.
4Measurement precision
If sensor surface is made highly sensitive to metal ions, then detection sensitivity is improved, but non-specific adsorption of other molecules increases
Solution Approach 1:
The patent applies specific functional groups (such as -COOH, -NH2, -SH) locally on the gate oxide surface to create selective binding sites for target metal ions. This local functionalization ensures high sensitivity for specific metal ions while reducing non-specific adsorption of other molecules, as the functional groups are strategically placed and chemically tuned for selective interaction.
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 method effectively quantifies low-concentration metal ions in various pH solutions, reducing production defects and costs by using a control solution for calibration and functional groups to enhance sensitivity and specificity, avoiding damage to FETs.
Implementation Method 1
utilization of the characteristics of field effect transistors (FET) exists for detecting the metal ions concentrations of solutions
Implementation Method 2
making the solution to be tested contact a gate oxide of the field effect transistor
Data Source
AI summary
The present invention discloses a detection method for low-concentration metal ions in solution, which avoids damage of strong acids and strong alkalis to the field effect transistors (FET) while using a control solution as a reference for calibration. By adjusting the electronic signals (resistance, inductance, current, voltage, etc.) generated by the solution to be tested and the control solution to be the same, the voltage difference therebetween is employed to quantitively infer the metal ions concentration of the solution to be tested.