IEC TS 62607-6-10:2021

Nanomanufacturing - Key control characteristics - Part 6-10: Graphene-based material - Sheet resistance: Terahertz time-domain spectroscopy

IEC TS 62607-6-10:2021(E) establishes a standardized method to determine the electrical key control characteristic
– sheet resistance (Rs)
for films of graphene-based materials by
– terahertz time domain spectroscopy (THz-TDS).
In this technique, a THz pulse is sent to the graphene-based material. The transmitted or reflected THz waveform is measured in the time domain and transformed to the frequency domain by the fast Fourier transform (FFT). Finally, the spectrum is fitted to the Drude model (or another comparable model) to obtain the sheet resistance.
• This non-contact inspection method is non-destructive, fast and robust for the mapping of large areas of graphene films, with no upper sample size limit.
• The method is applicable for statistical process control, comparison of graphene films produced by different vendors, or to obtain information about imperfections on the microscale such as grain boundaries and defects, etc.
• The method is applicable for graphene grown by chemical vapour deposition (CVD) or other methods on or transferred to dielectric substrates, including but not limited to quartz, silica (SiO2), silicon (Si), sapphire, silicon carbide (SiC) and polymers.
• The minimum spatial resolution is in the order of 300 µm (at 1 THz) given by the diffraction limited spot size of the THz pulse.

General Information

• Status: Published
• Publication Date: 13-Oct-2021
• ICS: 07.120 - Nanotechnologies
• Technical Committee: TC 113 - Nanotechnology for electrotechnical products and systems
• Drafting Committee: WG 8 - TC 113/WG 8
• Current Stage: PPUB - Publication issued
• Start Date: 03-Nov-2021
• Completion Date: 14-Oct-2021

Standards Content (Sample)

IEC TS 62607-6-10 ®
Edition 1.0 2021-10
TECHNICAL
SPECIFICATION
colour
inside
Nanomanufacturing – Key control characteristics –
Part 6-10: Graphene-based material – Sheet resistance: Terahertz time-domain
spectroscopy
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IEC TS 62607-6-10 ®
Edition 1.0 2021-10
TECHNICAL
SPECIFICATION
colour
inside
Nanomanufacturing – Key control characteristics –

Part 6-10: Graphene-based material – Sheet resistance: Terahertz time-domain

spectroscopy
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 07.120 ISBN 978-2-8322-1033-3

– 2 – IEC TS 62607-6-10:2021 © IEC 2021
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
3.1 General terms . 7
3.2 Key control characteristics measured according to this document . 9
3.3 Terms related to the measurement method described in this document . 10
4 General . 11
4.1 Measurement principle . 11
4.2 Sample preparation method . 13
4.3 Description of measurement equipment . 13
4.3.1 Principal components of a THz-TDS system . 13
4.3.2 Measurement configurations . 14
4.4 Supporting materials . 16
4.5 Calibration standards . 17
4.6 Measurement conditions . 17
5 Measurement procedure . 17
5.1 Calibration of the measurement equipment . 17
5.2 Detailed protocol of the measurement procedure . 17
5.3 Measurement accuracy . 19
6 Data analysis / interpretation of results . 20
7 Results to be reported . 24
7.1 Cover sheet . 24
7.2 Measurement conditions . 24
7.3 Measurement specific information . 24
7.4 Measurement results . 25
Annex A (informative) Worked example . 26
A.1 Background. 26
A.2 Measurement protocol . 26
A.3 Test report . 29
Annex B (informative) Application examples . 33
B.1 General . 33
B.2 Conductance map of CVD graphene on quartz . 33
Annex C (informative) Theoretical background . 35
C.1 Reflection and transmission of plane electromagnetic waves . 35
C.2 Transmission coefficient through a thin, conductive film . 37
C.3 Sheet conductivity of a thin, conductive film . 39
C.3.1 Reflection-mode geometry . 40
C.3.2 Transmission-mode geometry . 41
Annex D (informative) Considerations for custom-built systems . 43
D.1 Linearity of the THz-TDS detection system . 43
D.2 Calibration of custom-built equipment . 43
Bibliography . 44

Figure 1 – Time trace of a typical THz waveform. . 12
Figure 2 – Sample scheme comprised of a thin film of graphene on a dielectric
substrate. . 12
Figure 3 – Principal components of a classical THz-TDS system. 14
Figure 4 – Comparison of different transmission geometries. . 15
Figure 5 – Comparison of different reflection geometries . 16
Figure 6 – Photograph of a CVD monolayer of graphene on PET substrate . 21
Figure 7 – THz-TDS conductance and resistance maps of the sample . 21
Figure 8 – Analysis of high conductive areas in the conductivity map . 22
Figure 9 – Analysis of low conductive areas in the conductivity map . 22
Figure 10 – Analysis of low resistance areas in the resistance map . 23
Figure 11 – Analysis of high resistance areas in the resistance map . 23
Figure 12 – Conductance maps at two different frequencies: 0,5 THz and 0,75 THz . 24
Figure A.1 – Colour map of sheet resistance results at the selected frequency. Sheet
resistance map of the wafer at 0.5 THz, with step size 1 mm. . 32
Figure B.1 – Photograph of a graphene film on a 100 mm quartz wafer and related
conductivity map . 33
Figure B.2 – Detailed view of subsections . 34
Figure C.1 – Reflection and transmission for a thin film on a substrate . 35
Figure C.2 – Reflection and transmission for a thin film on a substrate. . 40

Table A.1 – Illustration of measurement protocol . 26
Table A.2 – Product identification . 30
Table A.3 – General material description . 30
Table A.4 – Sampling plan . 31
Table A.5 – Measurement related information . 31
Table A.6 – Measurement results: Sheet resistance at the selected frequency . 32

– 4 – IEC TS 62607-6-10:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
NANOMANUFACTURING – KEY CONTROL CHARACTERISTICS –

Part 6-10: Graphene-based material – Sheet resistance:
Terahertz time-domain spectroscopy

FOREWORD
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