IEC TS 62607-6-27:2025

IEC TS 62607-6-27 ®
Edition 1.0 2025-12
TECHNICAL
SPECIFICATION
Nanomanufacturing - Key control characteristics -
Part 6-27: Graphene-related products - Field-effect mobility for layers of two-
dimensional materials: field-effect transistor method
ICS 07.120  ISBN 978-2-8327-0909-2

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CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
3.1 General terms . 6
3.2 Key control characteristics measured according to this standard . 7
3.3 Terms related to the measurement method . 7
4 General . 8
4.1 Measurement principle . 8
4.2 Description of the measurement equipment . 9
4.3 Sample preparation method . 9
4.3.1 Sample preparation . 9
4.3.2 Fabrication of FETs with a 2D channel material . 9
4.4 Description of measurement equipment . 10
5 Measurement procedure . 10
6 Data analysis . 11
Annex A (informative) Worked example – 2PP and 4PP mobility measurements in
bottom-contacted WSe FETs . 13
A.1 Background . 13
A.2 Results to be reported. 14
Annex B (informative) Worked example – 2PP and 4PP mobility measurements in an
organic FET . 15
B.1 Background . 15
B.2 Results to be reported. 15
Annex C (informative) Worked example – Mobility measurements on WSe FETs . 17
C.1 Background . 17
C.2 Results to be reported. 18
Bibliography . 19

Figure 1 – Schematic of field-effect transistor where V and V are the gate voltage
g ds
and drain voltage applied with respect to source . 8
Figure 2 – Determination of field-effect mobility using a current–voltage transfer curve
of a FET . 9
Figure 3 – Schematic (left) and optical microscope image (right) of the four-terminal
configuration . 11
Figure 4 – Transfer curve (a) and corresponding transconductance (b) used to obtain
field-effect mobility which is extracted from the transconductance of a FET biased in
the linear regime . 11
Figure 5 – Mobilities obtained as a function of gate voltage . 12
Figure A.1 – Schematic of FET WSe used for 2PP mobility measurement . 13
Figure A.2 – Cross-sectional schematic . 13
Figure A.3 – Optical microscopic picture of a FET used for 4PP mobility measurement . 14
Figure B.1 – Device structure used for 2PP and 4PP measurements . 15
Figure B.2 – Comparison of the 2PP and 4PP mobility measurements in a rubrene
single-crystal organic FET for different gate voltages . 16
Figure C.1 – Colour-corrected optical image . 17
Figure C.2 – Schematic cross section of the device . 17
Figure C.3 – Temperature-dependent transfer characteristics showing the linear region
of device operation for V < −80 V . 18
GS
Figure C.4 – Extracted field-effect mobility at V = −95 V at different temperatures . 18
GS
Table A.1 – Comparison of 2PP and 4PP mobilities . 14

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Nanomanufacturing - Key control characteristics -
Part 6-27: Graphene-related products -
Field-effect mobility for layers of two-dimensional materials:
field-effect transistor method

FOREWORD
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IEC TS 62607-6-27 has been prepared by IEC technical committee 113: Nanotechnology for
electrotechnical products and systems. It is a Technical Specification.
The text of this Technical Specification is based on the following documents:
Draft Report on voting
113/899/DTS 113/940/RVDTS
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 Technical Specification is English.
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/publications.
A list of all parts in the IEC 62607 series, published under the general title Nanomanufacturing -
Key control characteristics, 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, or
– revised.
INTRODUCTION
Atomically thin two-dimensional (2D) materials are expected to be used for future electrical
subassemblies or electronic device applications. For these applications, it is obvious that
charge carrier mobility will be measured accurately, as an important figure of merit to indicate
the electrical operation speed and the efficiency of devices, since the mobility measured from
the devices with a 2D material-based channel are subject to errors resulted from large contact
resistance.
Two different types of mobility are typically used in semiconductor devices: Hall effect mobility
(µ ) and field-effect mobility (µ ). However, the extraction of the Hall effect mobility requires
H FE
a specialized structure and an application of magnetic field, which gives rise to difficulties
involving small Hall voltage (V ), is not adequate for practical semiconductor devices consisting
H
of field-effect transistors (FETs).
By contrast, field-effect mobility is extracted simply from a transfer curve obtained using a FET
in the device operation voltage region; therefore, it is more practical for industrial application of
semiconductor devices.
However, typical 2-point probe (2PP) transfer curves involve contact resistance as well as
channel resistance in FETs, which results in underestimated values of field-effect mobility. This
is critically important for 2D devices because most of 2D material-based devices show Schottky
contact property arising at the metal-2D material interface with the van der Waals gap which
results in large contact resistance compared to channel resistance.
By using 4-point probe (4PP) transfer curves, the true values of field-effect mobility, which are
only dependent on 2D channel, are obtained by excluding contact resistance.
From this reason, a standard method to determine 4PP-based field-effect mobility should be
established for 2D materials.
1 Scope
This part of IEC 62607 establishes a standardized method to determine the key control
characteristic
• field-effect mobility
for semiconducting two-dimensional (2D) materials by the
• field-effect transistor (FET) method.
For two-dimensional semiconducting materials, the field-effect mobility is determined by
fabricating a FET test structure and measuring the transconductance in a four-terminal
configuration.
– This method can be applied to layers of semiconducting two-dimensional materials, such as
graphene, black phosphorus (BP), molybdenum disulfide (MoS ), molybdenum ditelluride
(MoTe ), tungsten disulfide (WS ), and tungsten diselenide (WSe ).
2 2 2
– The four-terminal configuration improves accuracy by eliminating parasitic effects from the
probe contacts and cables
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 terminology databases 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 General terms
3.1.1
two-dimensional material
2D material
material, consisting of one or several layers with the atoms in each layer strongly bonded to
neighbouring atoms in the same layer, which has one dimension, its thickness, in the nanoscale
or smaller and the other two dimensions generally at larger scales
Note 1 to entry: The number of layers when a two-dimensional material becomes a bulk material varies depending
on both the material being measured and its properties. In the case of graphene layers, it is a two-dimensional
material up to ten layers thick for electrical measurements, beyond which the electrical properties of the material are
not distinct from those for the bulk (also known as graphite).
Note 2 to entry: Interlayer bonding is distinct from and weaker than intralayer bonding.
Note 3 to entry: Each layer may contain more than one element.
Note 4 to entry: A two-dimensional material can be nanoplatelets.
[SOURCE: ISO/TS 80004-13:2017, 3.1.1.1]
3.2 Key control characteristics measured according to this standard
3.2.1
key cont
...