Film bulk acoustic resonator structure based on all metal Bragg reflection layer

Abstract

The invention discloses a film bulk acoustic resonator (FBAR) structure based on an all metal Bragg reflection layer. The FBAR structure comprises a connecting antenna, an FBAR array duplexer or multiplexer, a low noise amplifier, an inhibition emitting signal filter, a receiving end attenuator, an emitting end attenuator and a power amplifier. The all metal Bragg reflection layer with excellent heat radiation capability is adopted, and the device heat sink is reduced, so the piezoelectric vibration heat energy can be effectively radiated from the all metal Bragg reflection layer and a substrate, the power capacitance of the FBAR filter is exponentially improved through the FBAR group structure in parallel connection, the same piezoelectric layer and the Bragg reflection layer are shared, the occurrence of device cracking condition caused by different heat impact and heat expansion factors is effectively reduced, finally, the power capacity of the filter based on the FBAR counting is integrally improved, and the characteristic of miniaturization of the FBAR filter is maintained. A whole wireless communication base station realizes the miniaturization.

Description

technical field [0001] The invention belongs to the technical field of communication equipment, and in particular relates to the miniaturization technology of radio frequency modules of high-power wireless communication base stations. technical background [0002] In order to support high-speed data services, high power capacity will become one of the main features of wireless communication base stations; at the same time, as the distribution of wireless communication base stations becomes more and more dense, they will tend to be more miniaturized and integrated, which will continue to promote Base station RF front-end circuits such as filters (including duplexers) tend to have high power capacity, miniaturization and integration. At present, in wireless communication base stations and other equipment, active devices can be integrated and microchip, only filters including multiplexers cannot be integrated and miniaturized, and the power capacity of filters in base stations ...

AI Technical Summary

Problems solved by technology

Dong Shurong, the applicant of this patent, proposed an aluminum-tungsten Bragg reflective layer in the paper "Research on FBAR Based on Al-W Multilayer Bragg Reflective Layer" in the "TFC07 National Thin Film Technology Symposium Abstracts Collection", but aluminum and Tungsten has a large difference in thermal expansion coefficient and low bonding force, so it is only suitable for low-power surface-mounted (SMR) FBARs

[0005] In the prior art, the Bragg reflection layer can well isolate the FBAR from the substrate, but there are disadvantages that limit the maximum power capacity of the FBAR device: (1) Due to the fact that the plastic, silicon dioxide, etc. in the Bragg reflection layer of the prior art The thermal conductivity of the material is relatively low, which inhibits the heat dissipation capability of the FBAR device to a certain extent. (2) The bonding force between metal and non-metal or plastic is low, and the difference in thermal expansion coefficient is large. shocks are prone to device failure

(3) Using only one FBAR cannot significantly increase the power capacity. At present, the power capacity of a single solid-state installation type FBAR is 3W, and the general requirement of the base station is between 10W-50W, so it is necessary to double the power capacity of the FBAR

The FBAR power capacity per unit area is fixed. Increasing the FBAR working area can double the FBAR power capacity, but this method has disadvantages: simply increasing the FBAR working area will increase the amplitude of the piezoelectric vibration peak position (generally the center position) of the FBAR. , The shortcomings of the solid-state mounting structure itself cause the FBAR loss to double, resulting in increased insertion loss and increased heat generation. The increase in heat will aggravate the FBAR and quickly reach its own operating temperature limit.

So simply increasing the area does not significantly increase the FBAR power capacity exponentially

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