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Preparation method of supporting type film bulk acoustic wave resonator

A thin-film bulk acoustic wave and resonator technology, which is applied in the direction of electrical components and impedance networks, can solve problems such as large residual stress of single-crystal thin films, lower yield, and cracks caused by wafer warping, so as to eliminate loss phenomena and alleviate Lattice mismatch and thermal mismatch, effects of improving stress state and crystal quality

Active Publication Date: 2019-02-05
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Commonly used epitaxial substrates include silicon substrates, sapphire substrates and SiC substrates. In general, silicon substrates have good thermal conductivity, can be prepared in large sizes, and are easy to integrate control circuits. However, there is a -18.9 % lattice mismatch and 11% thermal mismatch along the a-axis, resulting in excessive residual stress of the grown single crystal film and defects, causing wafer warpage and even cracks, which pose great challenges to the processing technology. Reduce yield

Method used

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  • Preparation method of supporting type film bulk acoustic wave resonator
  • Preparation method of supporting type film bulk acoustic wave resonator
  • Preparation method of supporting type film bulk acoustic wave resonator

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] The preparation method of the supported film bulk acoustic resonator of this embodiment includes the following steps:

[0048] (1) On the (111) plane Si substrate, grow a Mo metal insertion layer by radio frequency magnetron sputtering or molecular beam epitaxy;

[0049] (1-1) Cleaning: choose (111) Si substrate 1 through concentrated H 2 SO 4 :H 2 o 2 :H 2 O(1:1:3) and BOE:HF(20:1) cleaning to remove surface organic matter;

[0050] (1-2) Annealing: put the (111) Si substrate under a pressure of 3.0×10 -10 In Torr’s high-vacuum growth chamber, bake at 750°C for 30-60 minutes to remove pollutants on the substrate surface;

[0051] (1-3) Using a radio frequency magnetron sputtering machine, metal Mo with a purity of 99.99% is used as a sputtering target, and high-purity Ar (99.999%) is introduced as a sputtering gas during sputtering, and the total working pressure is 3~10Pa, target base distance is set to 60mm, vacuum degree is 4.0×10 -4 Pa, the substrate temper...

Embodiment 2

[0064] A preparation method of a supported film bulk acoustic resonator, comprising the following steps:

[0065] (1) On the cleaned and annealed (111) Si substrate, the Mo metal insertion layer is grown by radio frequency magnetron sputtering or molecular beam epitaxy, specifically:

[0066] Using a radio frequency magnetron sputtering machine, metal Mo is used as the sputtering target, and Ar gas is introduced as the sputtering gas during sputtering. at 4.0×10 -4 Pa, the substrate temperature is 150° C.-250° C. and a Mo metal insertion layer with a thickness of 100-200 nm is grown.

[0067] The cleaning is specifically: through concentrated H 2 SO 4 :H 2 o 2 :H 2 O=1:1:3 mixed solution and BOE:HF=20:1 mixed solution are cleaned to remove surface organic matter.

[0068] The annealing is specifically:

[0069] Place the substrate at a pressure of 2.5×10 -10 -3.0×10 -10 In Torr's high-vacuum growth chamber, bake at a high temperature of 600-750°C for 30-60 minutes to...

Embodiment 3

[0085] A preparation method of a supported film bulk acoustic resonator, comprising the following steps:

[0086] (1) On the cleaned and annealed (111) Si substrate, the Mo metal insertion layer is grown by radio frequency magnetron sputtering or molecular beam epitaxy, specifically:

[0087] Using a radio frequency magnetron sputtering machine, metal Mo is used as the sputtering target, Ar gas is introduced as the sputtering gas during sputtering, the total working pressure is 10Pa, the target base distance is set to 70mm, and the vacuum degree is higher than 4.0×10 -4 Pa, and the substrate temperature is 250°C to grow a Mo metal insertion layer with a thickness of 200nm.

[0088] The cleaning is specifically: through concentrated H 2 SO 4 :H 2 o 2 :H 2 O=1:1:3 mixed solution and BOE:HF=20:1 mixed solution are cleaned to remove surface organic matter.

[0089] The annealing is specifically:

[0090] Place the substrate at a pressure of 2.5×10 -10In Torr's high-vacuum ...

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Abstract

The invention discloses a preparation method of a supporting type film bulk acoustic wave resonator. The method comprises the following steps: growing a metal insertion layer on a (111) surface Si substrate, and continuing to grow a single crystal AIN film on the (111) surface Si substrate through a metal-organic chemical vapor deposition method, and finally depositing a metal electrode and a supporting layer on the single crystal AIN film. By means of film transfer, peeling, top electrode etching and other processes, a sandwich piezoelectric stacking structure of the film bulk acoustic wave resonator is formed at last. According to the preparation method disclosed by the invention, by importing the metal insertion layer, the mismatch phenomenon between the AlN epitaxial and the growth substrate is reduced, and the yield and the figure of merit of the device are improved on one hand; and on the other hand, a top electrode pattern can be directly etched after the film transfer and peeling procedures, so that the preparation procedures are simplified.

Description

technical field [0001] The invention relates to a preparation method of a resonator, in particular to a preparation method of a supporting type film bulk acoustic wave resonator. Background technique [0002] Film Bulk Acoustic Resonator (Film Bulk Acoustic Resonator, referred to as "FBAR") is a brand-new solution for radio frequency filters. By cascading multiple FBARs, it can satisfy the technology of radio frequency filters with a center frequency from 600MHz to 6GHz. Require. [0003] The core structure of FBAR consists of upper and lower layers of metal electrodes and a piezoelectric thin film sandwiched between them. Among them, the preparation of piezoelectric film is the core technology of FBAR. The piezoelectric material of FBAR usually adopts ZnO, PZT, AlN. Compared with the other two materials, AlN has the characteristics of large longitudinal wave sound velocity, low temperature coefficient, small intrinsic loss, good chemical stability, and compatibility with...

Claims

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Application Information

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IPC IPC(8): H03H3/007H03H3/02H03H9/02H03H9/15H03H9/17
CPCH03H3/0072H03H3/02H03H9/02H03H9/02015H03H9/02047H03H9/02244H03H9/15H03H9/174H03H2003/023H03H2003/027H03H2009/155H03H2009/02173
Inventor 李国强刘鑫尧李洁衣新燕
Owner SOUTH CHINA UNIV OF TECH
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