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, which is applied in the direction of electrical components and impedance networks, can solve the problems of device electroacoustic performance degradation and instability, and achieve the effects of eliminating parasitic capacitance, excellent sound wave reflection effect, and good sound wave reflection effect

Inactive Publication Date: 2011-03-30
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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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 ...

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
  • 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 one, combination figure 1 Description of this embodiment, a fixed film bulk acoustic resonator, which includes an upper electrode 1, a lower electrode 2, a piezoelectric film 3, a fully insulated Bragg reflector 4 and a Si substrate 5, an upper electrode 1, a lower electrode 2 and a piezoelectric The film 3 constitutes a sandwich structure of piezoelectric oscillator stack centered on the piezoelectric film 3, the piezoelectric oscillator stack is directly grown on the fully insulated Bragg reflector 4, and the fully insulated Bragg reflector 4 is grown on the Si substrate 5.

specific Embodiment approach 2

[0020] The second embodiment is that the difference between this embodiment and the fixed film bulk acoustic resonator described in the first embodiment is that the fully insulated Bragg reflector 4 is a layer of low acoustic impedance film 4-2. Low acoustic impedance film 4-2 is SiO 2 film.

[0021] The fully insulated Bragg reflector grid 4 described in this embodiment is a low acoustic impedance film layer 4-2 with a simple structure. The low acoustic impedance film layer 4-2 can be SiO deposited by a radio frequency magnetron sputtering system 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, and 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 fixing type film bulk acoustic wave resonator and a preparation method of its reflection grid. Background technique [0002] In recent years, SMR-FBAR technology has made breakthroughs and has been widely used in third-generation wireless communication systems. For example, it is used as a basic unit to make filters, duplexers and Frequency selection devices such as oscillators. SMR-FBAR is a piezoelectric oscillating stack composed of upper and lower electrodes and piezoelectric films, and the sandwich structure piezoelectric oscillating stack is directly grown to alternately formed by 3 to 7 groups of high / low acoustic impedance film layers. Above the Bragg reflector. figure 1 It is a schematic diagram of the structure of SMR-FBAR. The working principle of SMR-FBAR can be briefly described as: the use of piezoelectric film to convert electrical energy into sound energy, the sound wave is confined in the piezoelectric resonator...

Claims

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Application Information

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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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