IEC 62047-42:2022

IEC 62047-42
®

Edition 1.0 2022-09
INTERNATIONAL
STANDARD

colour
inside


Semiconductor devices – Micro-electromechanical devices –
Part 42: Measurement methods of electro-mechanical conversion characteristics
of piezoelectric MEMS cantilever

IEC 62047-42:2022-09(en)

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IEC 62047-42

®


Edition 1.0 2022-09




INTERNATIONAL



STANDARD









colour

inside










Semiconductor devices – Micro-electromechanical devices –

Part 42: Measurement methods of electro-mechanical conversion characteristics

of piezoelectric MEMS cantilever


























INTERNATIONAL

ELECTROTECHNICAL


COMMISSION





ICS 31.080.99 ISBN 978-2-8322-5714-2




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® Registered trademark of the International Electrotechnical Commission

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– 2 – IEC 62047-42:2022 © IEC 2022
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Test bed of MEMS piezoelectric thin film . 7
4.1 General . 7
4.2 Functional blocks and components . 9
4.2.1 General . 9
4.2.2 Displacement meter . 10
4.2.3 Power source . 10
4.2.4 Electric measurement instrument . 10
5 Microcantilever under testing . 11
5.1 General . 11
5.2 Measurement principle . 11
5.3 Measuring procedures of converse transverse piezoelectric coefficient . 12
5.4 Measuring procedures of direct transverse piezoelectric coefficient . 12
6 Test report . 13
Annex A (informative) Example of measuring method of piezoelectric MEMS cantilever . 15
A.1 General . 15
A.2 Measurement procedure . 15
A.2.1 Structure of piezoelectric microcantilevers . 15
A.2.2 Microfabrication process . 15
A.2.3 Mechanical properties of piezoelectric and non-piezoelectric layers . 16
A.2.4 Electric properties and resonance frequency of microcantilever . 17
A.2.5 Input displacement of microcantilever for direct piezoelectric coefficient
d
e . 18
31,f
A.3 Measurement results . 19
A.3.1 Converse piezoelectric measurement . 19
A.3.2 Direct piezoelectric measurement . 19
A.4 Test report . 20
Bibliography . 22

Figure 1 – Test bed of piezoelectric MEMS unimorph cantilever . 7
Figure 2 – Setup for measurement of converse piezoelectric effect . 9
Figure 3 – Setup for measurement of direct piezoelectric effect . 10
Figure A.1 – Structure and photograph of piezoelectric microcantilevers under testing. 15
Figure A.2 – Fabrication process of piezoelectric microcantilevers . 16
Figure A.3 – Frequency response of tip displacement of each piezoelectric

microcantilevers . 18
Figure A.4 – Tip displacement and converse piezoelectric coefficient as a function of
applied voltage . 19
Figure A.5 – Direct piezoelectric coefficient as a function of input tip displacement of
piezoelectric microcantilevers . 19

Table 1 – Symbols and designations of test bed . 8

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IEC 62047-42:2022 © IEC 2022 – 3 –
Table A.1 – Mechanical properties of piezoelectric layer . 16
Table A.2 – Mechanical properties of non-piezoelectric layer . 17
Table A.3 – Electric properties of microcantilever . 17
Table A.4 – Resonance frequencies of microcantilever . 17
d
Table A.5 – Input displacement for direct piezoelectric coefficient e . 18
31,f
Table A.6 – Test report . 20

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– 4 – IEC 62047-42:2022 © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

SEMICONDUCTOR DEVICES –
MICRO-ELECTROMECHANICAL DEVICES –

Part 42: Measurement methods of electro-mechanical conversion
characteristics of piezoelectric MEMS cantilever

FOREWORD
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rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC 62047-42 has been prepared by subcommittee 47F: Micro-electromechanical systems, of
IEC technical committee 47: Semiconductor devices. It is an International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
47F/414/FDIS 47F/417/RVD

Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.

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IEC 62047-42:2022 © IEC 2022 – 5 –
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
A list of all parts in the IEC 62047 series, published under the general title Semiconductor
devices – Micro-electromechanical devices, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

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– 6 – IEC 62047-42:2022 © IEC 2022
SEMICONDUCTOR DEVICES –
MICRO-ELECTROMECHANICAL DEVICES –

Part 42: Measurement methods of electro-mechanical conversion
characteristics of piezoelectric MEMS cantilever



1 Scope
This part of IEC 62047 specifies measuring methods of electro-mechanical conversion
characteristics of piezoelectric thin film on microcantilever, which is typical structure of actual
micro sensors and micro actuators. In order to obtain actual and precise piezoelectric coefficient
of the piezoelectric thin films with microdevice structures, and this document reports the schema
to determine the characteristic parameters for consumer, industry or any other applications of
piezoelectric devices. This document applies to piezoelectric thin films on microcantilever
fabricated by MEMS process.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological database for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
unimorph microcantilever
micro-scale cantilever composed of piezoelectric thin film and non-piezoelectric material,
typically thin silicon layer
Note 1 to entry: The piezoelectric thin films are deposited on bottom electrode. Top electrodes are prepared on the
piezoelectric thin films and input voltage are applied between top and bottom electrodes. Platinum is often used as
top and bottom electrodes for piezoelectric MEMS devices. The thickness of both top and bottom electrodes should
be thinner than that of piezoelectric thin film and non-piezoelectric layer of microcantilever. In case of direct
piezoelectric measurements, output signal is measured between bottom electrode and sensing top electrode as
described in 5.4.
3.2
converse transverse piezoelectric coefficient
transverse piezoelectric coefficient of the piezoelectric thin film calculated from strain or stress
caused by electric field or voltage
3.3
direct transverse piezoelectric coefficient
transverse piezoelectric coefficient of the piezoelectric thin film calculated from generated
charge or voltage caused by strain or stress

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IEC 62047-42:2022 © IEC 2022 – 7 –
4 Test bed of MEMS piezoelectric thin film
4.1 General
These measuring methods of the transverse piezoelectric properties apply to the unimorph
microcantilevers.

a) converse piezoelectric effect


b) direct piezoelectric effect

Key
1 electrode
2 piezoelectric thin film
3 non-piezoelectric layer
Figure 1 – Test bed of piezoelectric MEMS unimorph cantilever
Symbols and designations of test bed are given in Table 1.

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– 8 – IEC 62047-42:2022 © IEC 2022
Table 1 – Symbols and designations of test bed
Kind of properties Symbol Unit Designation
l m length of microcantilever
w m width of microcantilever
Dimension of
w m width of sensing top electrode
e
cantilever specimen
h
m thickness of non-piezoelectric layer
s
h m thickness of piezoelectric thin film
p
2
e effective transverse piezoelectric coefficient
C/m
31,f
d 2
effective transverse piezoelectric coefficient (direct
e C/m
31,f
effect)
c
N/Vm effective transverse piezoelectric coefficient
e
31,f
(converse effect)
c
N/Vm extrapolated effective transverse piezoelectric
Electro-mechanical e (V )
31,f in,0
coefficient at 0V (converse effect)
conversion properties
c
N/Vm minimum effective transverse piezoelectric
e (V )
31,f in,min
coefficient (converse effect at the lowest V )
in
c
N/Vm maximum effective transverse piezoelectric
e (V )
31,f in,max
coefficient (converse effect)
d m/V transverse piezoelectric coefficient (d-form)
31
C F capacitance between sensing top electrode and
bottom electrode
Q C output electric charge
out
Electrical properties
V V input peak-to-peak voltage
in
tan δ dielectric loss
ω rad/s angular frequency
2
E Young’s modulus of microcantilever
N/m
4
I area moment of inertia of microcantilever
m
3
ρ density of microcantilever
kg/m
D m tip displacement at x1
2
E
Young’s modulus of non-piezoelectric layer
N/m
s
Mechanical properties
ν Poisson’s ratio of non-piezoelectric layer
s
2
E Young’s modulus of piezoelectric thin film
N/m
p
ν Poisson’s ratio of piezoelectric layer
p
y m position of neutral plane of the unimorph cantilever
c
from the bottom
E E 2
elastic compliances of piezoelectric thin film
s , s m /N
11 12

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IEC 62047-42:2022 © IEC 2022 – 9 –
4.2 Functional blocks and components
4.2.1 General
Figure 1 provides typical structure of the specimens consisted of piezoelectric unimorph
microcantilever fabricated from a PZT (lead zirconate titanate (Pb[Zr(x)Ti(1-x)]O3)) thin film on
a Si(Silicon) or SOI (Silicon On Insulator) wafer. For the converse piezoelectric measurements,
the surface of the unimorph microcantilever is covered by single top electrode where actuation
voltage is applied (Figure 1 a)). Width of the top electrode is almost same as that of
microcantilever. On the other hand, for direct piezoelectric measurements, top electrode is
di
...