Amorphous Carbon Membrane for Hermetic MEMS
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Solution Overview
Problem
Existing MEMS devices face challenges in finding a coating that maintains membrane rigidity while ensuring chemical inertness, biocompatibility, hermeticity, and electromagnetic transparency, especially when operating in biological or aggressive environments.
Innovation Solution
An amorphous carbon membrane with a thickness between 1 nm and 50 nm, preferably 3 nm to 20 nm, is used, offering chemical inertness, biocompatibility, and hermeticity without significantly altering the membrane's rigidity, and featuring an sp3 hybridization rate of 20% to 40% for a Young's modulus of 100 GPa to 500 GPa, allowing it to be used as a standalone membrane or a protective coating for MEMS devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective coating is applied to the MEMS membrane, then chemical inertness, biocompatibility, and hermeticity are improved, but the rigidity of the membrane is modified
Solution Approach 1:
The patent applies an amorphous carbon coating with controlled thickness (5-50 nm) that forms a thin film protective layer on the membrane. This thin film provides the necessary chemical inertness, biocompatibility, and hermeticity while maintaining the membrane's flexibility and rigidity for proper operation in capacitive or piezoelectric transducers.
Solution Approach 2:
The patent specifies precise parameter ranges for the amorphous carbon coating, including thickness (5-50 nm) and sp3 hybridization rate (20-40%), to optimize the balance between protective properties and mechanical performance. By controlling these parameters, the coating provides reliability without significantly altering membrane rigidity.
2Strength
If the membrane thickness is reduced to improve flexibility, then the membrane operation is improved, but the hermeticity and chemical inertness are compromised
Solution Approach 1:
The patent creates a composite structure consisting of a thin flexible membrane substrate combined with an amorphous carbon coating layer. This composite provides both the flexibility of the thin membrane and the hermeticity and chemical inertness of the carbon coating, achieving properties that neither material alone could provide.
Solution Approach 2:
The amorphous carbon coating acts as a thin film that restores hermeticity to thin flexible membranes. The coating thickness (5-50 nm) is sufficient to provide barrier properties while maintaining overall membrane flexibility for proper transducer operation.
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 amorphous carbon membrane provides a flexible, chemically inert, and hermetic solution that maintains MEMS operation integrity, protecting both the device and environment, and remains stable up to 300°C, suitable for various MEMS applications including capacitive and piezoelectric transducers.
Implementation Method 1
The amorphous carbon membrane has an sp3
Implementation Method 2
The immersion medium imposes its pressure on the surface of a suspended membrane. It deforms under the action of this pressure.
Implementation Method 3
The deformation measurement can be done: or by capacitive effect. In this case, the deformable membrane is one of the plates of an electric capacitor. The deformation modifies the value of the capacitance
Implementation Method 4
or by piezoelectric effect. In this case, piezoelectric elements are mechanically associated with the membrane, so that their deformation is representative of the deformation of the membrane. The deformation of the piezoelectric elements results in the appearance of an electric potential difference
Data Source
Figure 1~4
AI summary
The invention relates to an amorphous carbon membrane for a microelectromechanical system, the amorphous carbon membrane having a thickness between 1 nm and 50 nm, and preferably between 3 nm and 20 nm, in which the amorphous carbon membrane has an sp3 hybridization rate between 20% and 40%.