Resonator Array Manufacturing for Gas Sensor Sensitivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gas sensors with a single resonator face challenges in detecting infinitesimal gas quantities due to limited sensitivity, and while multiple resonators in a matrix configuration are used to improve sensitivity, they often suffer from dispersion in resonant frequencies and quality factor issues.
Innovation Solution
A method of manufacturing a plurality of resonators with improved quality factor and reduced frequency dispersion by forming central and peripheral cavities, where peripheral membranes are removed through localized etching, allowing for a common electrode and more homogeneous stress distribution among central resonators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single resonator is used in a gas sensor, then the device complexity is low, but the sensitivity is insufficient to detect infinitesimal gas quantities
Solution Approach 1:
Multiple resonators are combined into a single sensor device, forming an array that collectively enhances sensitivity while maintaining a compact integrated structure. The resonators share common support infrastructure, reducing overall device complexity compared to multiple separate sensors.
2Measurement precision
If multiple resonators are arranged in a matrix configuration to improve sensitivity, then the sensitivity increases, but the quality factor decreases due to stress heterogeneity
Solution Approach 1:
The resonator array uses asymmetric boundary conditions by fixing only the periphery of the common support substrate while leaving the central region free. This creates a stress distribution where central resonators experience more uniform stress conditions, improving their quality factor while maintaining the sensitivity benefits of multiple resonators.
Solution Approach 2:
Different regions of the resonator array are designed with different fixation characteristics - peripheral resonators are constrained by the fixed periphery while central resonators benefit from a stress-free environment. This local differentiation optimizes the quality factor for central resonators while maintaining overall array sensitivity.
3Measurement precision
If multiple resonators are used in parallel to improve sensitivity, then the sensitivity improves, but the resonant frequency dispersion increases
Solution Approach 1:
Central resonators are positioned in a stress-free zone of the support substrate, creating locally optimized conditions that minimize stress-induced frequency variations. This local stress uniformity reduces resonant frequency dispersion among central resonators while the entire array maintains enhanced sensitivity.
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 approach enhances the collective sensitivity of gas sensors, enabling better detection of infinitesimal gas quantities and improving the quality factor, making them suitable for applications like smell sensors and mass spectrometry.
Implementation Method 1
a step to form membranes, called central membranes and peripheral membranes respectively, covering central cavities and peripheral cavities respectively, by the transfer of a coverage film on the front face of the support substrate
Implementation Method 2
step c) comprises localised etching of the coverage film, the localised etching comprises in particular wet etching or dry etching
Implementation Method 3
These membranes capable of vibrating in a direction perpendicular to the plane formed by said membranes are characterised by their resonant frequency
Implementation Method 4
gas sensors making use of gravimetric measurement as described in document [1] cited at the end of the description
Implementation Method 5
Operation of these sensors, described in document [2] cited at the end of the description, is based on the offset of the resonant frequency of their resonator, induced for example by the adsorption of chemical species on one face of said membrane
Data Source
AI summary
A method of manufacturing a plurality of resonators, each formed by a membrane sealing a cavity, includes forming a plurality of cavities starting from one face called the front face of a support substrate, the plurality of cavities comprising central cavities and peripheral cavities arranged around the assembly formed by the central cavities, and forming central membranes and peripheral membranes covering the central cavities and peripheral cavities, respectively, by the transfer of a coverage film on the front face of the support substrate. At least part of the peripheral membranes is removed.