ISO/TS 25138:2025

Technical
Specification
ISO/TS 25138
Third edition
Surface chemical analysis —
2025-02
Analysis of metal oxide films by
glow discharge optical emission
spectrometry
Analyse chimique des surfaces — Analyse de films d'oxyde
de métal par spectrométrie d'émission optique à décharge
luminescente
Reference number
© ISO 2025
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Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 2
5.1 Glow discharge optical emission spectrometer .2
5.1.1 General .2
5.1.2 Selection of spectral lines.2
5.1.3 Selection of glow discharge source type .2
6 Adjusting the glow discharge spectrometer system settings . 3
6.1 General .3
6.2 Setting the parameters of a DC source .4
6.2.1 Constant applied current and voltage .4
6.2.2 Constant applied current and pressure .5
6.2.3 Constant voltage and pressure .5
6.3 Setting the discharge parameters of an RF source .6
6.3.1 General .6
6.3.2 Constant applied voltage and pressure .6
6.3.3 Constant applied power and DC bias voltage .7
6.3.4 Constant effective power and RF voltage.7
6.4 Minimum performance requirements .7
6.4.1 General .7
6.4.2 Minimum repeatability .8
6.4.3 Detection limit .8
6.4.4 Control of lamp cleanliness and start-up performance .9
7 Sampling .11
8 Calibration .11
8.1 General .11
8.2 Calibration samples .11
8.2.1 General .11
8.2.2 Low alloy iron or steel samples . 12
8.2.3 Stainless-steel samples . 12
8.2.4 Nickel alloy samples . 12
8.2.5 Copper alloy samples . 12
8.2.6 Titanium alloy samples . 12
8.2.7 Silicon samples . 12
8.2.8 Aluminium alloy samples . 12
8.2.9 High-oxygen samples . 12
8.2.10 High-carbon samples . 12
8.2.11 High-nitrogen samples . 12
8.2.12 High-hydrogen samples . . 13
8.2.13 High-purity copper samples . 13
8.3 Validation samples . 13
8.3.1 General . 13
8.3.2 Hot-rolled low-alloy steel . 13
8.3.3 Oxidized silicon wafers. 13
8.3.4 TiN-coated samples. 13
8.3.5 Anodized Al O samples . 13
2 3
8.3.6 TiO -coated samples . 13
8.4 Determination of the sputtering rate of calibration and validation samples . 13
8.5 Emission intensity measurements of calibration samples . 15

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8.6 Calculation of calibration formulae . 15
8.7 Validation of the calibration . 15
8.7.1 General . 15
8.7.2 Checking analytical accuracy using bulk reference materials .16
8.7.3 Checking analytical accuracy using metal oxide reference materials .16
8.8 Verification and drift correction .16
9 Analysis of test samples . 17
9.1 Adjusting discharge parameters .17
9.2 Setting of measuring time and data acquisition rate .17
9.3 Quantifying depth profiles of test samples .17
10 Expression of results .18
10.1 Expression of quantitative depth profile .18
10.2 Determination of metal oxide mass per unit area .18
10.3 Determination of the average mass fractions of the elements in the oxide .19
11 Precision . 19
12 Test report . 19
Annex A (informative) Calculation of calibration constants and quantitative evaluation ofdepth
profiles.20
Annex B (informative) Suggested spectral lines for determination of given elements .31
Annex C (informative) Examples of oxide density and the corresponding quantity ρ .33
O
Annex D (informative) Report on interlaboratory testing of metal oxide films .
...