IEC 60747-5-18:2026

Semiconductor devices - Part 5-18: Optoelectronic devices - Light emitting diodes - Test method of the macro photoluminescence for epitaxial wafers of micro light emitting diodes

IEC 60747-5-18:2026 specifies the measuring methods of macro photoluminescence (PL) for red, green, and blue epitaxial wafers of micro light emitting diodes (LEDs) prior to chip fabrication processes. Wafer sizes being considered are 4 in, 6 in, and 8 in in diameter.

General Information

• Status: Published
• Publication Date: 10-Jun-2026
• ICS: 31.080.99 - Other semiconductor devices
• Technical Committee: SC 47E - Discrete semiconductor devices
• Drafting Committee: WG 9 - TC 47/SC 47E/WG 9
• Current Stage: PPUB - Publication issued
• Start Date: 11-Jun-2026
• Completion Date: 10-Jul-2026

Standards Content (Sample)

IEC 60747-5-18 ®
Edition 1.0 2026-06
INTERNATIONAL
STANDARD
Semiconductor devices -
Part 5-18: Optoelectronic devices - Light emitting diodes - Test method of the
macro photoluminescence for epitaxial wafers of micro light emitting diodes
ICS 31.080.99  ISBN 978-2-8327-1304-4

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CONTENTS
FOREWORD . 2
1 Scope . 4
2 Normative references . 4
3 Terms, definitions and abbreviated terms . 4
3.1 Terms and definitions . 4
3.2 Abbreviated terms. 6
4 Measuring methods. 6
4.1 General . 6
4.2 Principle . 6
4.3 Requirements . 7
4.3.1 Measuring conditions . 7
4.3.2 Measuring instruments and equipment . 7
4.4 Measurement setup . 9
5 Test . 11
5.1 Test items . 11
5.2 Test sequence . 11
5.3 Test report . 13
Annex A (informative) Test example . 14
Bibliography . 17

Figure 1 – Schematic illustration of the PL processes in semiconductors . 7
Figure 2 – Schematic diagram of the macro PL measurement setup . 10
Figure 3 – An example of the PL spectrum from a blue LED wafer . 10
Figure 4 – Sequence of the measurement of the macro PL of the micro LED epitaxial
wafer . 12
Figure A.1 – Peak PL signal distribution over a blue LED wafer . 14
Figure A.2 – Peak PL wavelength distribution over a blue LED wafer . 15
Figure A.3 – Centroid wavelength distribution over a blue LED wafer . 15
Figure A.4 – FWHM distribution over a blue LED wafer. 15
Figure A.5 – Integrated PL signal distribution over a blue LED wafer . 16

Table 1 – Summary of test report . 13

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Semiconductor devices -
Part 5-18: Optoelectronic devices - Light emitting diodes -
Test method of the macro photoluminescence for epitaxial wafers
of micro light emitting diodes

FOREWORD
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IEC 60747-5-18 has been prepared by subcommittee 47E: Discrete semiconductor devices, 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
47E/892/FDIS 47E/897/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.
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 60747 series, published under the general title Semiconductor
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, or
– revised.
1 Scope
This part of IEC 60747-5 specifies the measuring methods of macro photoluminescence (PL)
for red, green, and blue epitaxial wafers of micro light emitting diodes (LEDs) prior to chip
fabrication processes. Wafer sizes being considered are 4 in, 6 in, and 8 in in diameter.
2 Normative references
There are no normative references in this document.
3 Terms, definitions and abbreviated terms
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 Terms and definitions
3.1.1
PL signal
optical radiation emitted from the sample via photoluminescence
Note 1 to entry: PL signal is proportional to the radiant power.
3.1.2
spectral PL signal
dΦλ()
PL
Φλ()=
PL,λ
dλ
PL signal measured by a spectrometer per unit wavelength
Note 1 to entry: The unit for the spectral PL signal is arb. unit/nm.
Note 2 to entry: Spectral PL signal is proportional to the spectral radiant power.
3.1.3
peak PL signal
maximum value of the spectral PL signal
3.1.4
threshold
minimum spectral PL signal over which the integrated PL signal is evaluated
3.1.5
minimum wavelength limit
λ
min
lower limit of the integration in calculating the integrated PL signal
3.1.6
maximum wavelength limit
λ
max
upper limit of the integration in calculating the integrated PL signal
3.1.7
peak PL wavelength
λ
p
wavelength at which the spectral PL signal is the maximum
3.1.8
integrated PL signal
Φ
PL
spectral PL signal integrated over the wavelength
λ
max
Φ = Φ ()λdλ
PL PL,λ
∫
λ
min
Note 1 to entry: The minimum and maximum wavelengths are recommended to be smaller and greater than the
peak PL wavelength by 40 nm.
Note 2 to entry: A threshold value, 2 % of the peak PL signal, is recommended to remove the noise signal before
the integration.
Note 3 to entry: The unit for the integrated PL signal is arb. unit.
3.1.9
centroid wavelength
λ
c
wavelength at which the mean photon energy of the spectrum is specified [1]
λΦ ()λdλ
PL,λ
∫
λ =
c
Φ
PL
Note 1 to entry: For integration, the criteria of the upper/lower limits and the threshold value are the same as the
integrated PL signal.
hc
Note 2 to entry: The mean photon energy is related to the centroid wavelength as , where  is the
hv hv= h
λ
c
Φ
e
hν=
Planck constant and c is the speed of light in vacuum. The mean photon energy is defined by
λ
Φ dλ
e,λ
∫
hc
in IEC 60747-5-8:2019, where Φ is the radiant power and Φ is the spectral distribution (spectral radiant
e e,λ
power). The mean photon energy has a meaning of the radiant power divided by the total number of photons emitted
by the LED per unit time.
3.1.10
full width at half maximum
FWHM
range of a variable over which a given characteristic is greater than 50 % of its maximum value
Note 1 to entry: FWHM may be applied to characteristics such as radiation patterns, spectral linewidths, etc. and
the variable may be wavelength, spatial or angular properties, etc., as appropriate.
[SOURCE: IEC 60050-731:1991 [3], 731-01-57]
3.1.11
edge exclusion
distance from the edge of the wafer where no measurement is conducted
3.1.12
active region
region of the LED where LED radiation is emitted
3.1.13
transmittance optical density
D
τ
logarithm to base 10 of the reciprocal of the transmittance τ
D =−log τ
τ 10
Note 1 to entry: The transmittance optical density has unit one.
Note 2 to entry: This entry was numbered 845-04-66 in IEC 60050-845:1987.
[SOURCE: IEC 60050-845:2020, 845-24-072, modified – the accepted terms “optical density,
transmitt
...