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Film bulk acoustic resonators integrated on arbitrary substrates using a polymer support layer.
Guohao Chen1, Xinru Zhao1, Xiaozhi Wang1
1Department of Information Science and Electronic Engineering, Zhejiang University and Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou 310027, China.
Scientific Reports
|April 1, 2015
Summary
A new film bulk acoustic resonator (FBAR) architecture uses a polyimide layer for wave confinement, enabling integration on diverse substrates. This MEMS device offers comparable performance to traditional designs, with high fabrication yields.
Area of Science:
- Microelectromechanical Systems (MEMS)
- Acoustic Wave Devices
- Materials Science
Background:
- Film bulk acoustic resonators (FBARs) are crucial MEMS devices for filtering and sensing applications.
- Existing FBAR architectures necessitate acoustic mirrors or freestanding membranes, limiting integration flexibility.
- Current fabrication methods produce FBARs as discrete components, hindering substrate versatility.
Purpose of the Study:
- To demonstrate a novel FBAR architecture for fabrication and integration on arbitrary substrates.
- To achieve wave confinement using a polymer support layer, eliminating the need for traditional acoustic mirrors.
- To evaluate the performance and substrate independence of the new FBAR design.
Main Methods:
- Fabrication of FBARs on a polyimide support layer to achieve wave confinement.
- Characterization of FBAR performance (e.g., Q-factor) across various polymer thicknesses.
- Testing FBAR integration and performance on diverse substrates like silicon, copper, and glass.
Main Results:
- A critical polyimide layer thickness (d ~9 μm for ZnO FBARs at 1.3-2.2 GHz) was identified for optimal performance.
- FBARs fabricated on the polyimide support achieved a Q-factor of 470, comparable to 493 for membrane architecture devices.
- The polymer support rendered resonators insensitive to substrate properties, with over 95% yield on various materials.
Conclusions:
- The demonstrated FBAR architecture enables seamless integration on arbitrary substrates through polymer-based wave confinement.
- This innovation overcomes limitations of discrete component fabrication and substrate dependency in MEMS devices.
- The new design offers a viable alternative for advanced sensor and filter applications requiring flexible integration.
