Coplanar FET Gas Sensor Layout for Faster, More Specific Detection
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Solution Overview
Problem
Existing FET gas sensors suffer from limited sensitivity, response time, accuracy, and specificity in gas sensing due to their common architecture.
Innovation Solution
The FET gas sensor device features a configuration where the gate and semiconductor channel are arranged in the same plane, with a gas-receiving space between them, allowing direct coupling and interaction, enhancing sensitivity, response time, and specificity through a coplanar structure and the use of metal nanoparticles and dielectric layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a common FET architecture is used, then the device structure is simple, but the sensitivity and response time for gas sensing are limited
Solution Approach 1:
The gate electrode is segmented into multiple gates arranged in a specific pattern, creating distinct gas-receiving spaces between them. This segmentation allows gas molecules to access different regions of the semiconductor channel from multiple directions, enhancing the sensing sensitivity without requiring a complete redesign of the FET architecture.
Solution Approach 2:
The invention transitions from a conventional planar gate configuration to a three-dimensional arrangement where gates are positioned at different heights and orientations. This dimensional change creates gas-receiving spaces that allow gas molecules to approach the channel from multiple spatial directions, significantly improving gas sensing sensitivity and response time.
2Measurement precision
If gas-receiving spaces are introduced between gate and channel, then gas sensing sensitivity improves, but device fabrication complexity increases
Solution Approach 1:
The gate electrodes and gas-receiving spaces are integrated into a single structural unit that is fabricated together in one process sequence. The spaces are not separate components but are inherently formed by the arrangement of gates during standard FET fabrication, combining the gating function and gas reception function into a unified structure.
Solution Approach 2:
The gate electrodes serve multiple functions simultaneously: they provide electrical control over the channel, define the boundaries of gas-receiving spaces, and act as structural elements for gas molecule access. This multi-functionality eliminates the need for separate gas-receiving structures, simplifying fabrication while maintaining enhanced sensing capabilities.
3Reliability
If coplanar gate and channel arrangement is used, then coupling efficiency improves, but device area increases
Solution Approach 1:
Multiple gates are arranged in a nested or overlapping configuration where gates at different levels create interleaved electric fields. This nesting allows the gates to control the channel more effectively with reduced spacing, maintaining strong coupling while minimizing the overall device footprint.
Solution Approach 2:
The gate structure employs composite material layers with different dielectric properties optimized for both electrical control and gas permeability. This allows the gate to maintain strong electrical coupling with the channel while providing adequate gas access pathways, achieving both objectives within a compact area.
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
This configuration results in a highly sensitive, accurate, and specific gas sensing capability, with improved transconductance, miniaturization, and low-energy consumption, enabling efficient detection of gases like hydrogen.
Implementation Method 1
the arrangement of the gate(s) and the semiconductor channel in a same (common) plane (e.g. on the same side (surface) of a substrate) leads to an effective response of the FET gas sensor device to the gas received in the space(s) between the gate(s) and the semiconductor channel. As the space(s) is (are) directly coupled to the FET channel-gate coupling
Implementation Method 2
Field-effect transistors (FETs) may be used, among other things, in determining gas components in gas mixtures. For example, a gate electrode of the FET may react to gas components, thereby triggering a change in a control voltage applied to the gate electrode.
Data Source
Figure 1~2a
Figure 2b~2e
Figure 3a~3b
AI summary
A field effect transistor, FET, gas sensor device (100) arranged to sense gas, and a method of sensing gas by a FET gas sensor device, are provided. The FET gas sensor device comprises at least one gate (110a, 110b), a source (120), a drain (130), and a semiconductor channel (140). The semiconductor channel and the gate(s) form a FET channel-gate coupling (150) by which an applied gate potential is arranged to control a current flowing through the semiconductor channel. The FET gas sensor device further comprises space(s) (200) arranged between the gate(s) and the semiconductor channel and configured to receive gas, whereby received gas is arranged to influence electrical property(ies) of the FET channel-gate coupling, and wherein the FET gas sensor device is arranged to sense gas based on the influenced electrical property(ies) of the FET channel-gate coupling.