Surface acoustic wave filter with discontinuous substrate structure and preparation method of surface acoustic wave filter

A surface acoustic wave, discontinuous technology, applied in piezoelectric/electrostrictive/magnetostrictive devices, electrical components, circuits, etc., to achieve the effects of low price, increased insertion loss, and increased bandwidth

Pending Publication Date: 2021-06-15
ULTRATREND TECH INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the discontinuous structure technology for the propagation path of the surface acoustic wave filter is still blank.

Method used

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  • Surface acoustic wave filter with discontinuous substrate structure and preparation method of surface acoustic wave filter
  • Surface acoustic wave filter with discontinuous substrate structure and preparation method of surface acoustic wave filter
  • Surface acoustic wave filter with discontinuous substrate structure and preparation method of surface acoustic wave filter

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Such as figure 1 Shown is a discontinuous base structure SAW filter consisting of the following structures:

[0028] 1) substrate layer 1;

[0029] 2) The piezoelectric thin film layer 2 and the acoustic impedance discontinuous layer 3 contained therein arranged on the substrate layer;

[0030] 3) The interdigital transducer 4 arranged on the piezoelectric film layer.

[0031] As an optional embodiment, the substrate layer 1 is made of silicon, germanium, gallium arsenide, silicon carbide, sapphire, gallium nitride or aluminum nitride.

[0032] The piezoelectric thin film layer 2 is an AlN piezoelectric thin film, or an AlN piezoelectric thin film doped with one or more elements among Sc, Cr, Er, and its thickness is 100nm-10um.

[0033] The material of the acoustic impedance discontinuous layer 3 is a low-sonic material, a high-sonic material and a hollow structure, and its area is a uniform structure, a gradual structure or a periodically changing structure. In ad...

Embodiment 2

[0036] combined with figure 2 The preparation of a surface acoustic wave filter with a discontinuous base structure in this embodiment is described in detail.

[0037] 1) Prepare substrate material 1. In this embodiment, a silicon substrate is used as the substrate material. The silicon single crystal substrate used is a standard specification polished substrate, the surface is an EPI-ready polished surface cleaned by RCA, the roughness is less than 0.3nm, and the back is polished. Level, the roughness is 1±0.2μm.

[0038] 2) An AlN thin film 2 is grown on the substrate material 1 . This embodiment adopts the magnetron sputtering method (Sputter), the reaction chamber pressure is 0.3pa, the flow rate of nitrogen gas is 160sccm, the flow rate of argon gas is 40sccm, the sputtering power is 4KW, the temperature is 500°C, and the film thickness is 2um.

[0039] 3) An Al metal electrode layer 3 is fabricated on the surface of the piezoelectric film through a planar photolithog...

Embodiment 3

[0042] combined with image 3 The preparation of a surface acoustic wave filter with a discontinuous base structure in this embodiment is described in detail.

[0043] 1) Prepare substrate material 1. In this embodiment, a silicon substrate is used as the substrate material. The silicon single crystal substrate used is a standard specification polished substrate, the surface is an EPI-ready polished surface cleaned by RCA, the roughness is less than 0.3nm, and the back is polished. Level, the roughness is 1±0.2um.

[0044] 2) Using a negative photoresist to fabricate a structure 2 opposite to the design on the silicon (or other substrate) surface.

[0045] 3) An AlN thin film 3 is grown on the substrate material 1 . This embodiment adopts the magnetron sputtering method (Sputter), the reaction chamber pressure is 0.2pa, the flow rate of nitrogen gas is 140sccm, the flow rate of argon gas is 30sccm, the sputtering power is 3KW, the temperature is 500°C, and the film thicknes...

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Abstract

The invention provides a surface acoustic wave filter with a discontinuous substrate structure. The surface acoustic wave filter comprises the following structures: 1) a substrate layer 1; 2) a piezoelectric film layer 2 arranged on the substrate layer, and an acoustic impedance discontinuous layer 3 contained in the piezoelectric film layer 2; and 3) an interdigital transducer 4 arranged on the piezoelectric film layer. Through the surface acoustic wave filter of the invention, the acoustic impedance condition can be changed or periodic design can be carried out on the propagation path of the surface acoustic wave device (SAW), and the propagation characteristic of the surface acoustic wave is modulated, so that the improvement of the performance indexes such as the quality factor (Q value), the bandwidth and the insertion loss of the surface acoustic wave filter is finally realized. Compared with a traditional single crystal material, the piezoelectric film is adopted, the price is lower, and a gap space with discontinuous acoustic impedance can be easily prepared no matter a stripping process or an etching process is adopted.

Description

technical field [0001] The invention relates to the technical field of semiconductor material and device preparation, in particular to a surface acoustic wave filter with a discontinuous base structure and a preparation method thereof. Background technique [0002] Surface acoustic wave (SAW) is an elastic wave that propagates along the surface of an elastic solid or medium. Surface acoustic wave filter is a frequency selective device made of the piezoelectric effect and the physical characteristics of surface acoustic wave propagation. SAW filters have flexible design, analog / digital compatibility, small in-band attenuation, good anti-electromagnetic interference (EMI) performance, small size, light weight and high reliability. These characteristics make SAW filters widely used in base stations, navigation, mobile communications, etc. fields are widely used. [0003] The surface acoustic wave filter converts the input electrical signal into an acoustic signal through the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L41/187H01L41/316
CPCH10N30/853H10N30/076
Inventor 吴亮王琦琨付丹扬龚建超刘欢
Owner ULTRATREND TECH INC
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