Silicon micro piezoelectric microphone based on inn-plane polarization of ferroelectric PZT film and manufacture method thereof

An electric microphone and ferroelectric technology, applied in piezoelectric/electrostrictive transducer microphones, processes for producing decorative surface effects, piezoelectric/electrostrictive/magnetostrictive devices, etc., can solve the problem of micro-microphones The voltage sensitivity can not be improved and other problems, to achieve the effect of simplifying the micromachining process, improving the sensitivity, and good process compatibility

Inactive Publication Date: 2010-02-10
INST OF ACOUSTICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The silicon micro-piezoelectric microphone is usually a transducer of piezoelectric film bending vibration. The electrodes of the piezoelectric film are on its upper and lower surfaces. The piezoelectric micro-microphone uses the transverse piezoelectric constant d of the piezoelectric film 31 Work, ZnO film and PZT film are the most used piezoelectric film materials, the piezoelectric coefficient of PZT film is an order of magnitude larger than that of ZnO film, but due to the relatively large relative permittivity of PZT film, the voltage sensitivity of the micro microphone cannot be improved. Currently reported piezoelectric micro-microphones mainly use ZnO film as the piezoelectric material.

Method used

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  • Silicon micro piezoelectric microphone based on inn-plane polarization of ferroelectric PZT film and manufacture method thereof
  • Silicon micro piezoelectric microphone based on inn-plane polarization of ferroelectric PZT film and manufacture method thereof
  • Silicon micro piezoelectric microphone based on inn-plane polarization of ferroelectric PZT film and manufacture method thereof

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Experimental program
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Effect test

Embodiment 1

[0075] Embodiment 1, adopt the inventive method to prepare a silicon micro-piezoelectric microphone based on ferroelectric PZT film in-plane polarization work, its steps are as follows:

[0076] 1) Silicon wafer thermal oxidation

[0077] Clean the silicon wafer with acid cleaning solution and alkaline cleaning solution, then rinse and dry it with deionized water, put the silicon wafer into an oxidation furnace, and thermally oxidize and grow a 2 micron front high-temperature silicon dioxide layer on the front and back of the silicon wafer respectively 22 and back high temperature silicon dioxide layer 23, such as diagram 2-1 shown;

[0078] 2) Preparation of high-temperature silica circular mold layer 2

[0079] Spin-coat a positive photoresist on the front high-temperature silicon dioxide layer 22 and the back high-temperature silicon dioxide layer 23 respectively, and use a buffered hydrofluoric acid solution to etch the high-temperature silicon dioxide layer on the fron...

Embodiment 2

[0096] Embodiment 2, adopting the inventive method to prepare a silicon micro-piezoelectric microphone based on the in-plane polarization of the ferroelectric PZT film, the steps are as follows:

[0097] 1) Silicon wafer thermal oxidation

[0098] Clean the silicon wafer with acidic cleaning solution and alkaline cleaning solution, then rinse and dry it with deionized water, put the silicon wafer into an oxidation furnace, and thermally oxidize and grow a 4 micron front high-temperature silicon dioxide layer on the front and back of the silicon wafer respectively 22 and back high temperature silicon dioxide layer 23, such as diagram 2-1 shown;

[0099] 2) Preparation of high-temperature silica circular mold layer 2

[0100] Spin-coat a positive photoresist on the front high-temperature silicon dioxide layer 22 and the back high-temperature silicon dioxide layer 23 respectively, and use a buffered hydrofluoric acid solution to etch the high-temperature silicon dioxide layer ...

Embodiment 3

[0117] Embodiment 3, adopting the inventive method to prepare a silicon micro-piezoelectric microphone based on the in-plane polarization of the ferroelectric PZT film, its steps are as follows:

[0118] 1) Silicon wafer thermal oxidation

[0119] Clean the silicon wafer with acidic cleaning solution and alkaline cleaning solution, then rinse and dry it with deionized water, put the silicon wafer into an oxidation furnace, and thermally oxidize and grow a 4 micron front high-temperature silicon dioxide layer on the front and back of the silicon wafer respectively 22 and back high temperature silicon dioxide layer 23, such as diagram 2-1 shown;

[0120] 2) Preparation of high-temperature silica circular mold layer 2

[0121] Spin-coat a positive photoresist on the front high-temperature silicon dioxide layer 22 and the back high-temperature silicon dioxide layer 23 respectively, and use a buffered hydrofluoric acid solution to etch the high-temperature silicon dioxide layer ...

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Abstract

The invention relates to a silicon micro piezoelectric microphone based on the in-plane polarization of a ferroelectric PZT film and a manufacture method thereof, belonging to the technical field of silicon micro piezoelectric microphones. The silicon micro piezoelectric microphone is characterized by comprising electrodes, an in-plane polarized ferroelectric PZT film layer, a zirconia transitionlayer, a vibration film layer, a high-temperature silicon-dioxide round reverse-mold layer, a bulk-silicon etching square cup and a bulk-silicon etching mask layer which are sequentially arranged fromtop to bottom; the vibration film layer of the micro microphone has a round working area; capacitors comprising the PZT film and the electrodes are arranged in the center or at one edge of the roundworking area of a vibration film of the micro microphone; PZT film patterns are round or circular, and electrode patterns are in a concentric round interdigitated structure. The silicon micro piezoelectric microphone based on the in-plane polarization of the PZT film does not need to deposit bottom electrodes of the PZT film, thereby simplifying the process; in addition, The silicon micro piezoelectric microphone based on the in-plane polarization of the PZT film obviously improve the sensitivity of the micro piezoelectric microphone by changing the positions of the PZT film and interdigitatedelectrodes on the round working area of the vibration film and the distances between the interdigitated electrodes.

Description

technical field [0001] The invention relates to the field of silicon micro-piezoelectric microphones, in particular to a silicon micro-piezoelectric microphone based on the in-plane polarization of a ferroelectric PZT film and a preparation method thereof. Background technique [0002] Silicon micro microphones have broad application prospects in civil and national defense (such as mobile phones, audio-visual equipment, robot language recognition, active control of noise and vibration, battlefield reconnaissance network, security interception, etc.). Microphones mainly include capacitive and piezoelectric. At present, capacitive silicon micromicrophones have entered the market. Compared with capacitive microphones, piezoelectric micromicrophones have many advantages such as no need for polarization voltage, low internal resistance, and simple preparation. , has great application prospects, but its sensitivity is low at present, and it cannot meet the practical requirements. ...

Claims

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): H04R17/02B81B7/02H04R31/00B81C1/00
Inventor刘梦伟汪承灏李俊红
OwnerINST OF ACOUSTICS CHINESE ACAD OF SCI