Suspended Semiconductor Gas Sensor for Rapid Thermal Response
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional metal oxide semiconductor (MOS) gas sensors have inefficiencies in heating the gas-sensitive portion, leading to prolonged heating times and unnecessary energy consumption, as the heating element also heats other parts of the sensor, rather than just the gas-sensitive portion.
Innovation Solution
A semiconductor gas sensor device with a suspended structure, featuring a conductive layer, a non-suitable seed layer, and a porous gas sensing layer, where the gas sensing layer is supported directly by the seed layer and suspended above the conductive layer, allowing for targeted heating of the gas-sensitive portion without significantly heating other parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heating element is used to heat the gas-sensitive portion in traditional MOS gas sensors, then the gas-sensitive portion reaches the required temperature for detection, but other parts of the sensor are also heated unnecessarily, leading to prolonged heating times and increased energy consumption
Solution Approach 1:
The sensor is divided into distinct functional layers: a heating element layer and a gas-sensitive portion layer, separated by an intermediary layer. This segmentation allows the heating element to heat only the gas-sensitive portion without unnecessarily heating other parts of the sensor, thereby reducing energy consumption while achieving the required temperature for detection.
Solution Approach 2:
The intermediary layer is positioned between the heating element and the gas-sensitive portion to create localized heating. This layer ensures that thermal energy is concentrated at the gas-sensitive portion where it is needed, while minimizing heat transfer to other components, thus improving energy efficiency and reducing overall heating time.
2Temperature
If a heating element is activated to heat the gas-sensitive portion, then detection temperature is achieved, but heating time is prolonged due to thermal mass of other components
Solution Approach 1:
By segmenting the sensor structure into separate layers with the gas-sensitive portion positioned directly over the heating element and separated only by a thin intermediary layer, the thermal path is shortened. This reduces the thermal mass that needs to be heated, thereby decreasing the heating time while still achieving the required detection temperature.
Solution Approach 2:
The intermediary layer creates a localized thermal zone around the gas-sensitive portion, concentrating heat where it is needed. This localized heating approach minimizes the time required to reach detection temperature by avoiding the need to heat the entire sensor structure uniformly.
3Quantity of substance
If the gas-sensitive portion is made as a thick-film, then it provides sufficient sensing material, but the thermal time constant increases, slowing down the response time
Solution Approach 1:
The gas-sensitive portion is positioned in direct proximity to the heating element, separated only by a thin intermediary layer. This localized positioning ensures that thermal energy is concentrated on the gas-sensitive material, reducing its thermal time constant and enabling faster response times while maintaining sufficient material quantity for effective sensing.
Solution Approach 2:
The sensor structure transitions from a planar thick-film configuration to a vertically stacked layered structure. This dimensional change allows the gas-sensitive portion to be heated from below by the heating element, creating a more efficient thermal gradient that reduces the thermal time constant while maintaining adequate material thickness for sensing.
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 design enables rapid and efficient heating of the gas-sensitive portion, reducing thermal time constants to milliseconds, allowing for fast detection of target gases while minimizing energy consumption and avoiding unnecessary heating of other sensor components.
Implementation Method 1
The heating element is activated to heat the gas-sensitive portion to a temperature that is suitable for detecting a target gas
Implementation Method 2
Chemisorption is one type of adsorption that may occur at the grain boundaries 22 in the presence of the target gas
Data Source
AI summary
A semiconductor gas sensor device includes a substrate, a conductive layer supported by the substrate, a non-suitable seed layer, and a porous gas sensing layer portion. The non-suitable seed layer is formed from a first material and includes a first support portion supported by the conductive layer, a second support portion supported by the conductive layer, and a suspended seed portion extending from the first support portion to the second support portion and suspended above the conductive layer. The porous gas sensing layer portion is formed from a second material and is supported directly by the non-suitable seed layer in electrical communication with the conductive layer. The first material and the second material form a non-suitable pair of materials.