IEC TS 62876-3-4:2025

IEC TS 62876-3-4 ®
Edition 1.0 2025-12
TECHNICAL
SPECIFICATION
Nanomanufacturing - Reliability assessment -
Part 3-4: Linearity of output characteristics for metal contacted 2D
semiconductor devices
ICS 07.120  ISBN 978-2-8327-0928-3

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CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
3.1 General terms regarding the sample . 7
3.2 General terms regarding the sample test. 8
4 Recommended sample preparation . 9
4.1 Device structure of the sample under test . 9
4.2 Sample preparation method . 9
4.2.1 Sample preparation . 9
4.2.2 Fabrication of FETs . 9
4.2.3 Consideration on sample design . 10
5 Measurement procedure . 11
5.1 Measurement equipment . 11
5.2 Calibration of measurement equipment . 11
5.3 Measurement procedure . 11
6 Data analysis / interpretation of results . 12
Annex A (informative) Worked example – Linearity of I-V curves for bottom-contacted
WSe FETs . 17
A.1 Background . 17
A.2 Results to be reported. 18
Annex B (informative) Worked example – Linearity of I-V curves for edge-contacted
MoS FETs . 20
B.1 Background . 20
B.2 Results to be reported. 21
Annex C (informative) Worked example – Linearity of I-V curves for WS FETs with
current saturation . 23
C.1 Background . 23
C.2 Results to be reported. 23
Bibliography . 24

Figure 1 – Metal–semiconductor (SC) junctions and their respective band diagrams . 6
Figure 2 – Schematic of a FET . 8
Figure 3 – Schematic output curves obtained from ohmic and non-ohmic contact . 12
Figure 4 – Schematic I-V conductance of output curves obtained from Ohmic contact
without and with current saturation . 13
Figure 5 – Schematic I-V conductance of output curves obtained from non-ohmic
contact without and with current saturation . 14
Figure 6 – Schematic I-V output curves and linearities obtained from ohmic contact . 15
Figure 7 – Schematic I-V output curves and linearities obtained from non-ohmic
contact . 16
Figure A.1 – Device fabrication processing steps to induce ohmic-like transport by
conducing O plasma treatment [3] . 17
Figure A.2 – (a), (b) Output curves and (c), (d) corresponding linearities collected from
pristine and plasma-treated WSe FET at various V . 18
2 G
Figure A.3 – Time dependent output curves and corresponding linearities collected
from pristine and plasma-treated WSe FETs for various gate voltages applied . 19
Figure B.1 – Cross-sectional view of edge-contact interface formed between MoS and
metal that was used to induce ohmic-like contact . 20
Figure B.2 – (a, b) Output curves and (c, d) corresponding linearities collected from Pd
and Sb edge-contacted MoS FETs with various gate voltages applied . 21
Figure B.3 – (a-c) Time dependent output curves and (d) corresponding linearities
collected from pristine and aged Sb edge-contacted MoS FETs for various V . 22
2 g
Figure C.1 – (a, d) Output curve, (b, e) the first derivative curve (dI /dV ) and (c, f)
D D
linearity for devices with channel thicknesses of 2,1 nm and 7 nm, respectively . 23

Table 1 – Allowed channel lengths to apply this document when contact resistance is
limited up to 20 % and 50 % . 11

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Nanomanufacturing - Reliability assessment -
Part 3-4: Linearity of output characteristics for metal
contacted 2D semiconductor devices

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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IEC TS 62876-3-4 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
113/920/DTS 113/938/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 62876 series, published under the general title Nanomanufacturing -
Reliability assessment, 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) nano-materials are expected to be used for future
electrical sub-systems or electronic device applications.
– I-V measurements are the fundamental electrical characterization technique for assessing
reliability of field-effect transistors (FETs) as well as semiconductor device performance.
– The performance of the FET is mainly characterized by measuring the output (drain current
as a function of drain voltage at different gate voltages) and transfer (drain current as a
function of gate voltage at different drain voltages) characteristics.
– If metallic electrical contacts have negligible effects on electronic transport, output
characteristics show a linear behaviour according to the following formula:
μWC
n ox
 
I V−VV , where I is the drain current, μ is the electron mobility, W is the
( ) d
d g th d n
 
L
transport channel width, C is the gate oxide capacitance, V is the gate voltage, V is the
ox g th
threshold voltage, and V is the drain voltage, which can indicate ohmic contact. In contrast,
d
when metallic contact gives rise to high resistance to electronic transport, output
characteristics do not show the linear behaviour, following the formula:
μWC
n ox
 
I VV− V−×I 2R [1] where R is the contact resistance, which is
( )
( )
D g th dd C c
 
L
interpreted as Schottky contact which can bring about a reliability issue of ohmic-contact
semiconductor transistor operation.
– Current transport at the metallic contact of 2D semiconductor material-based FETs mainly
consists of two distinct components: thermal emission where charge injection occurs over
the energy barrier and tunnelling (field emission) where the charge injection occurs through
the barrier formed at the metal-semiconductor interface.
– Current transport at the metallic contact of 2D material-based FETs can be limited due to
the van der Waals (vdW) gap that forms at the metal-2D semiconductor interface, creating
a high contact resistance and suppressing current transport of the 2D FETs. However, being
different from 2D material-based FETs, conventional FETs have good ohmic contact and
usually have not had reliability issues in metallic contacts. But 2D materials involving vdW
gap can give rise to uncontrollable Schottky contact leading to a serious reliability issue of
metallic contact. See Figure 1.
– In addition, the lack of efficient doping techniques for 2D materials at the metal-
semiconductor junction, also contributes to the high contact resistance and suppressed
current transport, in contrast to 3D bulk semiconductors such as silicon. See Figure 1 for
comparison.
– The issues arising from the vdW gap at the 2D material-metal interface and thus the resulted
high contact resistance pose challenges to the reliability of metallic electrical contacts of 2D
FETs. Therefore, we propose a standard method to quantify the reliability of the metallic
electrical contacts by analyzing current-voltage (I-V) characteristics of 2D FETs.
=
=
a) Typical metal/bulk SC interface b) Au-MoS interface with vdW
Key
E Fermi level of metal
F
E conduction band of 2D SC
c
E valence band of 2D SC
v
TB tunnel barrier height
SB Schottky barrier height
A, B, B’ and C Different regions in the current path from the metal to the SC.
Blue arrows from top to bottom: Thermionic emission, thermionic field emission, and field emission (tunnelling).
Figure 1 – Metal–semiconductor (SC) junctions and their respective band diagrams
– Therefore, it is important to obtain accurate current-voltage (I-V) characteristics and to
assess linearity of the I-V output curves, so that reliable 2D FET device operation can be
ensured. The reliability of the devices also needs to be evaluated over an extended time
period.
NOTE Both capital and small letters in subscripts of device parameters are used with no differences each other,
dependent on users (typically device engineers): e.g. I is the same as I , V is the same as V , and V is the same
D d D d G
as V .
g
1 Scope
This part of IEC 62876 establishes a standardized guideline to assess
– reliability of metallic interfaces
of ohmic-contacted field-effect transistors (FETs) using 2D nano-materials by quantifying
– linearity of current-voltage (I-V) output curves
for devices with various materials combinations of van der Waals (vdW) interfaces.
For metallic interfaces with 2D materials (eg. graphene, MoS , MoTe , WS , WSe , etc) and
2 2 2 2
metals (eg. Ti, Cr, Au, Pd, In, Sb, etc), the reliability of ohmic contact is quantified.
For FETs consisting of 2D materials-based channels (eg. MoS , MoTe , WS , WSe , etc), the
2 2 2 2
reliability of ohmic contact when varying contacting metal, channel length, channel thickness,
applied voltage, and surface treatment condition is quantified.
The reliability of the metallic contacts is quantified from the linearity of I-V characteristics
measured over extended time periods.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC TS 62607-6-5, Nanomanufacturing - Key control characteristics - Part 6-5: Graphene-
based materials - Contact and sheet resistance: transmission line measurement
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 regarding the sample
3.1.1
two-dimensional material
material which has its thickness constrained within the nanoscale or smaller and consist of
between one and several layers
Note 1 to entry: These materials are thus termed two-dimensional (2D) materials as they have one dimension at
the nanoscale or smaller, with the other two dimensions generally at scales larger than the nanoscale.
EXAMPLE Graphene, monolayer and few layer versions of hexagonal boron nitride, molybdenum disulphi
...