Pyroelectric AlN MEMS Sensor with Periodic Electrode for Wavelength Selectivity
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Solution Overview
Problem
Current MEMS infrared sensors require optical filters to selectively absorb specific wavelengths of infrared light, which increases manufacturing costs and limits the production of multi-channel sensors, whereas a technology that eliminates the need for filters could reduce costs and enable a single platform for various wavelength absorptions.
Innovation Solution
A MEMS sensor with a pyroelectric layer and patterned periodic electrode structure, where the periodicity of the structure is less than or equal to the target infrared wavelength, allowing for selective absorption of infrared radiation without the need for optical filters, utilizing materials like AlN for the pyroelectric layer and Molybdenum for electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical filters are used to selectively absorb specific wavelengths of infrared light, then wavelength selectivity is improved, but manufacturing cost increases and device complexity increases
Solution Approach 1:
The patent extracts the optical filtering function from separate external filters and integrates it directly into the sensor element through periodic structures. This eliminates the need for separate optical filter components while maintaining wavelength selectivity, thereby reducing device complexity and manufacturing cost.
Solution Approach 2:
The patent merges the wavelength selection function with the infrared absorption function by integrating periodic structures directly into the sensor element. This combination allows a single component to perform both functions, reducing the overall number of parts and simplifying the device architecture.
2Measurement precision
If optical filters are used to selectively absorb specific wavelengths of infrared light, then wavelength selectivity is improved, but manufacturing cost increases
Solution Approach 1:
The patent extracts the optical filtering function from separate external filters and integrates it directly into the sensor element through periodic structures. This eliminates the need for separate optical filter components while maintaining wavelength selectivity, thereby reducing device complexity and manufacturing cost.
Solution Approach 2:
The patent creates a universal sensor platform where the periodic structures can be designed to detect different wavelengths by adjusting the period size. This multi-functional capability allows a single manufacturing process to produce sensors for various wavelengths, reducing overall manufacturing cost compared to producing separate filtered sensors for each wavelength.
3Measurement precision
If optical filters are used to selectively absorb specific wavelengths of infrared light, then wavelength selectivity is improved, but the ability to produce multi-channel sensors on a single platform is limited
Solution Approach 1:
The patent creates a universal sensor platform where the periodic structures can be designed to detect different wavelengths by adjusting the period size. This multi-functional capability allows a single manufacturing process to produce sensors for various wavelengths, reducing overall manufacturing cost compared to producing separate filtered sensors for each wavelength.
Solution Approach 2:
The patent enables wavelength tuning by changing the periodicity parameter of the structures. By adjusting this single parameter, the same sensor platform can detect different infrared wavelengths, providing multi-channel capability without requiring different filter components for each channel.
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
The solution enables the production of sensors that can selectively absorb infrared radiation in specific bands, reducing manufacturing costs and allowing for multiple wavelength absorptions on a single platform, suitable for applications like NDIR gas sensors, without the need for additional optical filters.
Implementation Method 1
the sensor elements absorb incident infrared, transfer them to heat, measure the temperature, and then output electric signals. Materials such as pyroelectric material
Implementation Method 2
Recent studies in the area of selective tunable infrared sensors propose the use of thermopile structures or bolometers having the surface plasmon or metamatelial structures with periodic structures of metal
Data Source
AI summary
A MEMS sensor for detecting electromagnetic waves in a particular frequency range is provided. In a preferred embodiment, the MEMS sensor comprises a bottom substrate layer; a first electrode layer over the substrate layer; a pyroelectric layer over the first electrode layer; and a second electrode layer over the pyroelectric layer; wherein a top electrode layer is patterned with a periodic structure that has a periodicity less than or equal to target infrared wavelength.