Multi-Pixel Gas Sensor Fabrication Using Reused Mask Regions
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Solution Overview
Problem
Miniaturized gas sensors often lack the capability to detect multiple gas species efficiently and are challenging to manufacture, particularly for highly integrated sensors.
Innovation Solution
A method involving a multiple-mask process using sputtering to apply different sensor materials and functionalizing treatments to functional regions on a silicon-based substrate, enabling the creation of a multi-pixel gas sensor with independently addressable sensor elements, each with unique gas sensing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single gas sensor type is manufactured using conventional methods, then the manufacturing process is simple, but the sensor can only detect one gas species
Solution Approach 1:
The sensor device is divided into multiple functional regions on a single substrate, where each region contains different sensor materials for detecting different gas species. This segmentation allows multi-gas detection capability while maintaining a unified manufacturing process, resolving the contradiction between versatility and complexity.
Solution Approach 2:
A single sensor device structure is designed to perform multiple functions by incorporating different sensor materials in different functional regions. The unified substrate and common manufacturing process enable the device to detect multiple gas species simultaneously, achieving multi-functionality without proportionally increasing manufacturing complexity.
2Adaptability or versatility
If multiple individual masks are used for each gas sensor type, then each gas species can be detected, but the manufacturing effort and complexity increase significantly
Solution Approach 1:
Multiple sensor material deposition steps that would traditionally require separate masks are merged into a single mask-based process. Different sensor materials are deposited in sequence through the same mask structure, allowing multiple gas detection capabilities to be achieved without multiplying the mask manufacturing effort.
Solution Approach 2:
The same mask structure is reused across multiple deposition steps to create different functional regions. Instead of creating unique masks for each gas sensor type, the mask design is copied and applied repeatedly with different sensor materials, significantly reducing the number of unique mask patterns that must be manufactured.
3Volume of moving object
If miniaturized gas sensors are manufactured with high integration, then the device size is reduced, but the ability to detect multiple gas species is compromised
Solution Approach 1:
Instead of expanding the sensor device area horizontally to accommodate multiple sensor types, the patent utilizes the vertical dimension by depositing multiple sensor material layers through the same functional regions. This layered approach enables multi-gas detection within a compact footprint, resolving the contradiction between miniaturization and versatility.
Solution Approach 2:
Multiple sensor materials are nested within the same functional region structure, with different materials deposited in sequence to form a layered configuration. This nesting allows multiple detection capabilities to be packed into a single miniaturized sensor element, maintaining small device size while achieving multi-gas detection.
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
Enables the production of a miniaturized, highly integrated gas sensor capable of detecting multiple gas species with high sensitivity and selectivity, achieved through the use of semiconducting metal oxides and varying sensor materials and treatments, allowing for efficient gas detection.
Implementation Method 1
In the presence of oxygen, for example in air, at elevated temperatures, for example between 150° C. and 400° C., oxygen can be adsorbed at the surface of the semiconducting metal oxide
Implementation Method 2
Due to electron trapping effects in the semiconducting metal oxide, which are caused by the oxygen absorbance, the electrical resistance of the semiconducting metal oxide changes
Implementation Method 3
The first sensor material and/or the second sensor material and/or any further sensor materials in addition to the first and/or second sensor material, are different to each other. Different materials of sensor materials can, in particular, imply that the sensor materials have different components and/or a different compositions. Different materials can, in particular, provide different sensitivities to different gas species.
Data Source
AI summary
In an embodiment a method includes providing a substrate with an electrical functional layer comprising a plurality of functional regions, wherein the functional regions are electrically addressable independently from each other, wherein the plurality of functional regions comprises at least a first group of functional regions and a second group of functional regions, wherein the first group is different from the second group, and wherein at least one functional region is part of the first group and of the second group and performing a multiple-mask process by applying a first mask on the electrical functional layer, wherein the first mask exposes the functional regions of the first group and covers all other functional regions, applying a first sensor material over the exposed functional regions by sputtering, removing the first mask, applying a second mask on the electrical functional layer, wherein the second mask exposes the functional regions of the second group and covers all other functional regions, applying a second sensor material over the exposed functional regions by sputtering and/or performing a functionalizing treatment in the exposed functional regions and removing the second mask.