ISO 14707:2021

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 14707
ISO/TC 201/SC 8
Surface chemical analysis —
Secretariat: JISC
Glow discharge optical emission
Voting begins on:
2020­12­04 spectrometry (GD-OES) —
Introduction to use
Voting terminates on:
2021­01­29
Analyse chimique des surfaces — Spectrométrie d'émission optique à
décharge luminescente — Introduction à son emploi
RECIPIENTS OF THIS DRAFT ARE INVITED TO
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OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 14707:2020(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2020

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ISO/FDIS 14707:2020(E)

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© ISO 2020
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ISO/FDIS 14707:2020(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 2
5.1 Glow discharge optical emission source . 2
5.2 Optical unit . 5
5.3 Photoelectric detectors and measuring devices . 5
6 Procedure. 5
6.1 Verification tests of apparatus . 5
6.1.1 General. 5
6.1.2 Glow discharge source . 6
6.1.3 Optical unit and electric measuring device . 7
6.2 Determination . 7
6.2.1 General. 7
6.2.2 Preparation of the required calibration specimens . 7
6.2.3 Setting up of measuring conditions and analysis of specimens . 8
6.2.4 Quality check of results . 8
6.2.5 Test report . 8
Annex A (informative) Safety .10
Bibliography .12
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ISO/FDIS 14707:2020(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www .iso .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 201, Surface chemical analysis,
Subcommittee SC 8, Glow discharge spectroscopy.
This third edition cancels and replaces the second edition (ISO 14707:2015), of which it constitutes a
minor revision.
The main changes compared to the previous edition are as follows:
— Editorial mistakes have been modified.
A list of all parts in the ISO 14707 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
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ISO/FDIS 14707:2020(E)

Introduction
Glow discharge optical emission spectrometry (GD-OES) is used to determine the elemental composition
of solid samples. GD-OES can be used for either bulk or depth profile analysis. In bulk analysis, changes
in elemental composition with depth into the specimen are assumed to be negligible. In contrast,
the main goal of depth profile analysis is usually to gain information concerning such changes of
composition. Layer thicknesses amenable to GD-OES depth profiling range from a few nanometres to
approximately one hundred micrometres. An average of the concentration within the crater will be
obtained and therefore the lateral resolution of GD­OES corresponds to the inner diameter of the anode.
As is true for any instrumental analysis method, the quality of a GD-OES analysis depends markedly on
the correct optimization and operation of the instrumentation. This document provides guidelines of
practice that are to be followed to ensure that GD-OES analyses are of the highest possible quality.
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 14707:2020(E)
Surface chemical analysis — Glow discharge optical
emission spectrometry (GD-OES) — Introduction to use
1 Scope
This document provides guidelines that are applicable to bulk and depth profiling GD-OES analyses.
The guidelines discussed herein are limited to the analysis of rigid solids, and do not cover the analysis
of powders, gases or solutions. Combined with specific standard methods which are available now and,
in the future, these guidelines should enable the regulation of instruments and the control of measuring
conditions.
Although several types of glow discharge optical emission sources have been developed over the
years, the Grimm type with a hollow anode accounts for a very large majority of glow discharge optical
emission devices currently in use both for dc and rf sources. It should be noted, however, that the
cathode contact is often located at the back of the sample, in e.g. the Marcus type source, rather than at
the front as in the original Grimm design. It should be clearly understood that the guidelines contained
herein are equally applicable to both and other source designs and that the Grimm type source is used
only as an example.
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.
ISO 3497, Metallic coatings — Measurement of coating thickness — X-ray spectrometric methods
ISO 5725­1, Accuracy (trueness and precision) of measurement methods and results — Part 1: General
principles and definitions
ISO 5725­2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method
for the determination of repeatability and reproducibility of a standard measurement method
ISO 5725­3, Accuracy (trueness and precision) of measurement methods and results — Part 3: Intermediate
measures of the precision of a standard measurement method
ISO 5725­4, Accuracy (trueness and precision) of measurement methods and results — Part 4: Basic
methods for the determination of the trueness of a standard measurement method
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 3497, ISO 5725-1, ISO 5725-2,
ISO 5725-3 and ISO 5725-4 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
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ISO/FDIS 14707:2020(E)

4 Principle
Analysis by GD-OES involves the following operations:
a) preparation of the sample to be analysed, generally in the form of a flat plate or disc of dimensions
appropriate to the instrument or analytical requirement (round or rectangular samples with a
width of more than 3 mm, generally 20 mm to 100 mm, are suitable);
b) atomization and excitation of the analytes to be determined by means of ion sputtering and inter-
particle collisions occurring in the glow discharge plasma;
c) measurement of the emission intensities of characteristic spectral lines of the analytes (for depth
profiling, emission intensities are recorded as a function of time);
d) determination of the analyte concentrations contained in the sample by calibration with reference
materials of known composition (for depth profiling, the sputtered depth as a function of time is also
determined by calibration with reference materials of known composition and sputtering rates).
A diagram of a typical GD-OES system is presented in Figure 1. GD­OES is based on the use of a glow
discharge device as an optical emission source. The glow discharge device consists of a vacuum chamber
filled with a supporting gas, usually argon. The glowing plasma, from which the discharge takes its
name, is maintained by a controlled high voltage of 200 V to 2 000 V applied between the anode and
cathode in the plasma gas. The solid sample to be analysed serves as the cathode.
Atomization of sample material in the glow discharge is the result of cathode sputtering, the destruction
of the negative electrode (cathode) in a gas discharge due to the impact of fast charged and neutral
particles. Ions formed in the plasma are accelerated toward the cathode surface by the electric field in
the plasma. When an ion or neutral atom collides with the surface, its kinetic energy may be transferred
to atoms on the surface, causing some of these surface atoms to be ejected into the plasma. Once in
the plasma, these sputtered sample atoms may be ionized and excited through inelastic collisions with
electrons or other species. The majority of these excited analyte atoms and ions then emit characteristic
optical emission upon relaxing into the lower electronic state. The optical emission is analysed by an
optical spectrometer containing a dispersive element, normally a diffraction grating. The intensities of
element-specific spectral lines are translated to electrical signals by means of appropriate detectors.
A polychromator is commonly employed, so that many elements can be quantified simultaneously.
Spectral lines that are not contained in the line set of the polychromator can be accessed by means of a
scanning monochromator, if one is available. CCD instruments also exist, where a spectrum over a wide
spectral range can be measured continuously. In practice almost all elements in the periodic table can
be determined, including metals, metalloids and non­metals.
5 Apparatus
At a minimum, the apparatus consists of the following:
5.1 Glow discharge optical emission source
A diagram of a Grimm type glow discharge optical emission device is shown in Figure 2. Several
modifications in the device have been introduced by instrument manufacturers. As noted in Clause 4,
the sample effectively serves as the cathode. The anode takes the form of a tube with an inner diameter
of 1 mm to 10 mm, typically 4 mm. The distance between the front face of the anode and the surface of
the cathode is usually between 0,1 mm and 0,3 mm. As a result, ion sputtering is confined to a circular
region of the sample surface with a diameter approximately equal to the inner diameter of the anode.
The glow discharge device requires several peripheral pieces of equipment for its operation. These
include an electric power supply, one or two vacuum pumps, a source of plasma gas, a means of
delivering that gas into the device in a controlled manner and a vacuum gauge. A cooling device, such as
a metal block with circulating cooling liquid, is sometimes necessary for thin samples.
a) Source parameters
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ISO/FDIS 14707:2020(E)

Glow discharge devices may be operated in either direct current (dc) or radio-frequency (rf) mode.
Combinations of these two modes, such as the use of an rf voltage superposed onto a dc voltage, have
also been reported. In both the dc and rf power modes, a pulsed discharge is also employed for switching
the applied power periodically. The following operations shall be conducted with careful attention to
safety (see Annex A):
1) For dc operation, the pertinent electrical parameters are discharge current (1 mA to 200 mA) and
voltage (200 V to 2 000 V). In addition to the electrical parameters, other parameters are important
for the characteristics of the device. These include the inner diameter of the anode (1 mm to 10 mm),
gas type and purity (for example, argon, > 99,999 %), gas flow rate or gas pressure introduced
(100 ml/min to 500 ml/min, 100 Pa to 1 500 Pa, see note below) and physical characteristics of
the sample material (for example, secondary electron emission yield and sputtering yield). The
combined effects of all of these factors determine the spectrochemical character of the glow
discharge plasma. Gener
...