Solidly mounted film bulk acoustic resonator and method for preparing fully insulated Bragg reflecting grating thereof

A thin-film bulk acoustic wave and Bragg reflection technology, applied in electrical components, impedance networks, etc., can solve the problems of electro-acoustic performance degradation and instability of devices, and achieve the effects of eliminating parasitic capacitance, excellent sound wave reflection effect, and good sound wave reflection effect.

Inactive Publication Date: 2012-12-12
HARBIN INST OF TECH
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Problems solved by technology

[0003] In order to solve the problem that the parasitic capacitance exists in the application of the existing fixed film bulk acoustic resonator, which further leads to the significant decline and instability of the electroacoustic performance of the device, the present invention proposes a fixed film bulk acoustic resonator and its fully insulated Bragg reflection Grid preparation method

Method used

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  • Solidly mounted film bulk acoustic resonator and method for preparing fully insulated Bragg reflecting grating thereof
  • Solidly mounted film bulk acoustic resonator and method for preparing fully insulated Bragg reflecting grating thereof

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specific Embodiment approach 1

[0019] Specific implementation mode 1. Combination figure 1 Description of this embodiment, the fixed film bulk acoustic resonator, which includes an upper electrode 1, a lower electrode 2, a piezoelectric film 3, a fully insulated Bragg reflection grating 4 and a Si substrate 5, an upper electrode 1, a lower electrode 2 and a piezoelectric The thin film 3 forms a piezoelectric oscillating stack sandwich structure centered on the piezoelectric thin film 3 , the piezoelectric oscillating stack grows directly on the fully insulated Bragg reflective grating 4 , and the fully insulated Bragg reflective grating 4 grows on the Si substrate 5 .

specific Embodiment approach 2

[0020] Embodiment 2. The difference between this embodiment and the solid-mount thin-film bulk acoustic resonator described in Embodiment 1 is that the fully insulated Bragg reflection grating 4 is a low acoustic impedance film layer 4-2, and the Low acoustic impedance film layer 4-2 is SiO 2 film.

[0021] The fully insulated Bragg reflection grating 4 described in this embodiment has a single low acoustic impedance film layer 4-2, and has a simple structure. This low acoustic impedance film layer 4-2 can utilize the radio frequency magnetron sputtering system to deposit SiO 2 film.

specific Embodiment approach 3

[0022] Embodiment 3. This embodiment is a further limitation of the fixed-film bulk acoustic resonator described in Embodiment 2. The film thickness of the low acoustic impedance film layer 4 - 2 is 300-2000 nm.

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Abstract

The invention relates to provides a solidly mounted film bulk acoustic resonator (SMR-FBAR) and a method for preparing a fully insulated Bragg reflecting grating thereof. The invention solves the problem that parasitic capacitance exists in application of the existing SMR-FBAR, so that the electroacoustic performance of the device is substantially reduced and unstable. The resonator is characterized in that a piezoelectric oscillation pile of sandwich structure, which is formed by upper and lower electrodes and a piezoelectric film, is directly grown on the fully insulated Bragg reflecting grating; and the fully insulated Bragg reflecting grating is formed by alternating 3-7 groups of high / low impedance film layers. The method comprises the following steps: 1. designing a system; 2. cleaning a substrate; 3. depositing a first low impedance SiO2 film layer; 4. depositing silicon as an adhesive layer; 5. depositing a first high impedance amorphous diamond film layer; 6. depositing silicon film as an adhesive layer; and 7. depositing a second low impedance SiO2 film layer. The invention is suitable for the application fields requiring stable electroacoustic performance.

Description

technical field [0001] The invention relates to a solid-mount thin-film bulk acoustic wave resonator and a preparation method for a reflection grid thereof. Background technique [0002] In recent years, the technology of the fixed film bulk acoustic resonator (SMR-FBAR) has made a breakthrough, and has been widely used in the third generation wireless communication system, such as used as the basic unit to make filters, duplexers and Frequency selective devices such as oscillators. SMR-FBAR is a piezoelectric oscillating stack composed of upper and lower electrodes and piezoelectric films, and the piezoelectric oscillating stack with a sandwich structure is directly grown to a structure composed of 3 to 7 sets of high / low acoustic impedance film layers alternately. above the Bragg grating. figure 1 is a schematic diagram of the structure of SMR-FBAR. The working principle of SMR-FBAR can be briefly described as: the piezoelectric film is used to convert electrical energy...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H03H9/25H03H3/02
Inventor 朱嘉琦刘罡王赛陆晓欣刘远鹏
Owner HARBIN INST OF TECH
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