MEMS Sensor Layered Support Suppressing Oxygen Interference
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Solution Overview
Problem
Existing sensors with MEMS structures face challenges in achieving high detection sensitivity, particularly due to interference from oxygen in the air which affects the sensitivity of gas detection.
Innovation Solution
The sensor design includes a base with a fixed electrode and a movable portion supported by a first support portion, which comprises layers including oxygen and specific elements like Pt, Pd, or Ti. A second layer with different elements like Si or Al is provided to suppress the influence of oxygen, enhancing detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a MEMS structure is used in the sensor, then the sensor can achieve high detection sensitivity for gas concentration changes, but the detection sensitivity is degraded by interference from oxygen in the air
Solution Approach 1:
The support portion is segmented into multiple layers: a first support layer, a first layer containing the first element (Pt, Pd, or Ti), and a second layer containing the second element (Si or Al). This segmentation allows each layer to serve a specific function - the first layer responds to target gas while the second layer suppresses oxygen interference, resolving the contradiction between detection sensitivity and oxygen interference
Solution Approach 2:
The support portion uses a composite structure combining different materials (Pt, Pd, Ti, Si, Al) in specific layers. The first element layer provides catalytic activity for target gas detection, while the second element layer provides oxygen suppression. This composite material approach enables simultaneous achievement of high detection sensitivity and resistance to oxygen interference
2Measurement precision
If the first layer includes Pt, Pd, or Ti to enhance gas detection, then detection sensitivity improves, but the sensor becomes more susceptible to oxygen interference
Solution Approach 1:
The second layer containing Si or Al acts as an intermediary between the first layer (Pt, Pd, or Ti) and the environment. This intermediary layer suppresses oxygen diffusion to the first layer, protecting the catalytic elements from oxygen interference while maintaining their gas detection capability
Solution Approach 2:
Different regions of the support portion have different properties: the first layer has high catalytic activity for target gas detection, while the second layer has oxygen suppression properties. This local differentiation of material properties allows the sensor to simultaneously achieve high sensitivity and stability
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 allows for high detection sensitivity, capable of detecting small changes in the concentration of detection target gases such as hydrogen, with improved accuracy compared to traditional sensors.
Implementation Method 1
the first layer is reduced by a detection target gas around the first support portion
Implementation Method 2
stress is generated between the first layer and the first support layer. The stress is, for example, tensile stress. Thereby, the shape of the first support portion changes
Data Source
AI summary
According to one embodiment, a sensor includes a base, a fixed electrode, a first fixed portion, a first support portion, and a movable portion supported by the first support portion. The base includes first and second regions. The fixed electrode and the first fixed portion are fixed to the first region and the second region, respectively. The first support portion is connected to the first fixed portion, and includes a first support layer, a first layer, and a second layer. The first layer is provided between the first support layer and at least a part of the second layer in a first direction from the first support layer to the second layer. The first layer includes oxygen and a first element including at least one selected from the group consisting of Pt, Pd and Ti. The second layer includes oxygen and a second element different from the first element.