Suspended-Gate FET Membrane for Selective Analyte Detection
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Solution Overview
Problem
Existing chemical and biological sensors fail to meet the requirements for high selectivity, sensitivity, miniaturization, and cost-effectiveness, while being susceptible to environmental disturbances and requiring complex setups.
Innovation Solution
A suspended gate field effect transistor (SG FET) with a membrane structure that forms a displaceable gate electrode, incorporating a sensitive layer that interacts with analytes to induce stress deformation, allowing for sensitive and selective detection with minimal environmental interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional chemical sensors are used, then detection capability is achieved, but selectivity and sensitivity requirements are not met
Solution Approach 1:
The gate electrode is divided into a fixed gate portion and a movable gate portion, where the movable portion can displace in response to analyte detection. This local differentiation allows the sensor to achieve both detection capability and high selectivity through the specific mechanical response of the movable gate region to target analytes.
Solution Approach 2:
The gate electrode transitions from a static structure to a dynamic one with a movable gate portion that can displace. This dynamic structure enables the sensor to respond selectively to analytes through mechanical displacement, improving both sensitivity and selectivity while maintaining detection capability.
2Area of moving object
If sensor miniaturization is pursued, then integration density improves, but manufacturing complexity increases
Solution Approach 1:
The gate electrode is segmented into fixed and movable portions, allowing the sensor to be miniaturized while maintaining functionality. The segmented structure enables compact integration without proportionally increasing manufacturing complexity, as each segment can be fabricated using standard processes.
Solution Approach 2:
The movable gate portion is implemented as a thin film or membrane structure that can be suspended over the channel. This flexible structure enables miniaturization and high integration density while being compatible with existing thin-film fabrication techniques, avoiding excessive manufacturing complexity.
3Measurement precision
If high sensitivity is achieved, then detection accuracy improves, but energy consumption increases
Solution Approach 1:
The sensor replaces thermal or optical detection mechanisms with a mechanical displacement mechanism. The movable gate portion physically moves in response to analyte binding, converting chemical interactions directly into mechanical motion that modulates the electrical signal. This mechanical substitution achieves high sensitivity without the high energy consumption associated with heating or illumination-based methods.
4Reliability
If sensor reliability is improved, then service life extends, but manufacturing cost increases
Solution Approach 1:
The sensor design changes the operational parameters by using electrical field effects and mechanical displacement instead of thermal or optical methods. This parameter change improves reliability and service life through reduced thermal stress and material degradation, while maintaining compatibility with low-cost 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 SG FET provides high selectivity, linear response, and energy efficiency, with minimal hysteresis and no need for heating elements, enabling low-cost, miniaturized, and long-lasting sensors.
Implementation Method 1
an interaction of the material of the sensitive layer with the component of the analyte results in a stress induced deformation of the sensitive layer
Implementation Method 2
an interaction of the material of the sensitive layer with the component of the analyte results in a stress induced deformation of the sensitive layer
Implementation Method 3
stress induced deformation of the sensitive layer and in a deflection (Δx) of the displaceable gate region of the membrane structure due to the stress induced deformation of the sensitive layer
Implementation Method 4
the deflection of the displaceable gate region results in a change of a gate capacitance (ΔCG) and in a correspondent change of a channel conductivity (ΔX14)
Data Source
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AI summary
A suspended gate field effect transistor (10) comprises a semiconductor substrate (12) having a channel region (14) between a first contact region (16-1) and a second contact region (16-2), a membrane structure (20), which spans over the channel region (14) and provides a vacuity (23) with the opposing semiconductor substrate (12) over the channel region (14), wherein the membrane structure (20) forms a suspended gate electrode of the field effect transistor and has at least one displaceable gate region (20-1), and a sensitive layer (22), which comprises a material for interacting with a component (24-A) of an analyte (24), wherein the sensitive layer (22) is arranged on the membrane structure (20) so that an interaction of the material of the sensitive layer (22) with the component (24-A) of the analyte (24) results in a stress induced deformation of the sensitive layer (22) and in a deflection (Δx) of the displaceable gate region (20-1) of the membrane structure (20) due to the stress induced deformation of the sensitive layer (22).