Graphite Film MEMS Vibrator for Thin, Chemically Resistant Oscillators
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Solution Overview
Problem
Conventional silicon-MEMS oscillators face issues with mechanical strength, chemical resistance, and complexity in structure, which limits their performance and commercialization, especially due to the use of silicon as a resonator material.
Innovation Solution
A MEMS vibrator utilizing a graphite film with a thickness of 50 nm to 20 μm and a Young's modulus of 700 GPa or more, directly bonded or bonded with a silicon member using a metal or resin layer, offering enhanced mechanical strength and chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silicon is used as a resonator material in MEMS oscillators, then the device can be manufactured with existing semiconductor processes, but the mechanical strength and chemical resistance are insufficient
Solution Approach 1:
The patent employs silicon carbide (SiC) as a composite material that combines the manufacturability of semiconductor materials with superior mechanical strength and chemical resistance. SiC integrates well with existing CMOS fabrication processes while providing enhanced physical properties that overcome the limitations of pure silicon resonators.
2Ease of manufacture
If silicon is used as a resonator material, then existing semiconductor manufacturing processes can be utilized, but chemical resistance is poor
Solution Approach 1:
Silicon carbide serves as a chemically resistant composite material that maintains compatibility with standard semiconductor manufacturing processes. The SiC resonator structure provides excellent chemical inertness, enabling the MEMS oscillator to operate reliably in chemically aggressive environments where silicon would deteriorate.
3Reliability
If a complicated structure is adopted to improve temperature stability, then the oscillator is less affected by environmental temperature, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent achieves temperature stability by changing the material parameter from silicon to silicon carbide, which has a lower temperature coefficient of frequency. This material substitution provides inherent temperature compensation, reducing the need for complex temperature compensation circuits or structures while maintaining stable oscillation frequency across varying environmental conditions.
4Ease of manufacture
If silicon resonators are used in MEMS products, then the devices can be manufactured, but the thickness cannot be decreased due to mechanical strength limitations
Solution Approach 1:
Silicon carbide's superior specific strength (strength-to-density ratio) enables the fabrication of thinner resonator structures compared to silicon. The SiC material maintains adequate mechanical strength at reduced thicknesses, allowing for miniaturized MEMS oscillators with lower profile heights while preserving structural integrity and resonant performance.
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 graphite-MEMS vibrator achieves high mechanical strength, chemical resistance, and compactness, enabling the development of high-performance, lightweight MEMS devices with improved sensitivity and resistance to environmental factors.
Implementation Method 1
a vibrating film including a graphite film... the graphite film having a Young's modulus along a graphite film plane direction of 700 GPa or more
Data Source
AI summary
The present disclosure relates to a MEMS vibrator or the like that has excellent chemical resistance and an excellent mechanical strength and that is easily thinned. The present disclosure is a MEMS vibrator comprising: a vibrating film including a graphite film; and a silicon member supporting the vibrating film, the graphite film having a thickness of 50 nm or more and less than 20 μm, and the graphite film having a Young's modulus along a graphite film plane direction of 700 GPa or more.