1、 Reference number ISO/TS 25138:2010(E) ISO 2010TECHNICAL SPECIFICATION ISO/TS 25138 First edition 2010-12-01 Surface chemical analysis Analysis of metal oxide films by glow-discharge optical-emission spectrometry Analyse chimique des surfaces Analyse de films doxyde de mtal par spectromtrie dmission
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7、SO/TS 25138:2010(E) ISO 2010 All rights reserved iiiContents Page Foreword iv 1 Scope1 2 Normative references1 3 Principle .1 4 Apparatus.2 4.1 Glow-discharge optical-emission spectrometer 2 5 Adjusting the glow-discharge spectrometer system settings3 5.1 General .3 5.2 Setting the parameters of a D
8、C source.4 5.3 Setting the discharge parameters of an RF source .5 5.4 Minimum performance requirements6 6 Sampling 8 7 Calibration8 7.1 General .8 7.2 Calibration specimens 8 7.3 Validation specimens10 7.4 Determination of the sputtering rate of calibration and validation specimens 11 7.5 Emission
9、intensity measurements of calibration specimens.12 7.6 Calculation of calibration equations .12 7.7 Validation of the calibration .12 7.8 Verification and drift correction.14 8 Analysis of test specimens 14 8.1 Adjusting discharge parameters .14 8.2 Setting of measuring time and data acquisition rat
10、e.14 8.3 Quantifying depth profiles of test specimens 15 9 Expression of results15 9.1 Expression of quantitative depth profile.15 9.2 Determination of metal oxide mass per unit area 15 9.3 Determination of the average mass fractions of the elements in the oxide16 10 Precision 16 11 Test report17 An
11、nex A (normative) Calculation of calibration constants and quantitative evaluation of depth profiles18 Annex B (informative) Suggested spectral lines for determination of given elements.29 Annex C (informative) Examples of oxide density and the corresponding quantity O 30 Annex D (informative) Repor
12、t on interlaboratory testing of metal oxide films.31 Bibliography36 ISO/TS 25138:2010(E) iv ISO 2010 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International St
13、andards 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
14、 take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committee
15、s is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. In other circumstances, particul
16、arly when there is an urgent market requirement for such documents, a technical committee may decide to publish other types of document: an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in an ISO working group and is accepted for publication if it i
17、s approved by more than 50 % of the members of the parent committee casting a vote; an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting a vote. An
18、 ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is confirmed, it is reviewed again after a further three years, at which time it must either
19、 be transformed into an International Standard or be withdrawn. 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. ISO/TS 25138 was prepared by Technica
20、l Committee ISO/TC 201, Surface chemical analysis, Subcommittee SC 8, Glow discharge spectroscopy. TECHNICAL SPECIFICATION ISO/TS 25138:2010(E) ISO 2010 All rights reserved 1Surface chemical analysis Analysis of metal oxide films by glow-discharge optical-emission spectrometry 1 Scope This Technical
21、 Specification describes a glow-discharge optical-emission spectrometric method for the determination of the thickness, mass per unit area and chemical composition of metal oxide films. This method is applicable to oxide films 1 nm to 10 000 nm thick on metals. The metallic elements of the oxide can
22、 include one or more from Fe, Cr, Ni, Cu, Ti, Si, Mo, Zn, Mg, Mn and Al. Other elements that can be determined by the method are O, C, N, H, P and S. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the editi
23、on cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 14284, Steel and iron Sampling and preparation of samples for the determination of chemical composition ISO 14707, Surface chemical analysis Glow discharge optical emission
24、 spectrometry (GD-OES) Introduction to use ISO 16962:2005, Surface chemical analysis Analysis of zinc- and/or aluminium-based metallic coatings by glow-discharge optical-emission spectrometry 3 Principle The analytical method described here involves the following processes: a) Cathodic sputtering of
25、 the surface metal oxide in a direct-current or radio-frequency glow-discharge device. b) Excitation of the analyte atoms in the plasma formed in the glow-discharge device. c) Spectrometric measurement of the intensities of characteristic spectral-emission lines of the analyte atoms as a function of
26、 sputtering time (depth profile). d) Conversion of the depth profile in units of intensity versus time to mass fraction versus depth by means of calibration functions (quantification). Calibration of the system is achieved by measurements on calibration specimens of known chemical composition and me
27、asured sputtering rate. ISO/TS 25138:2010(E) 2 ISO 2010 All rights reserved4 Apparatus 4.1 Glow-discharge optical-emission spectrometer 4.1.1 General The required instrumentation includes an optical-emission spectrometer system consisting of a Grimm type 1or similar glow-discharge source (direct-cur
28、rent or radio-frequency powered) and a simultaneous optical spectrometer as described in ISO 14707, capable of providing suitable spectral lines for the analyte elements. The inner diameter of the hollow anode of the glow-discharge source shall be in the range 2 mm to 8 mm. A cooling device for thin
29、 specimens, such as a metal block with circulating cooling liquid, is also recommended, but not strictly necessary for implementation of the method. Since the principle of determination is based on continuous sputtering of the surface metal oxide, the spectrometer shall be equipped with a digital re
30、adout system for time-resolved measurement of the emission intensities. A system capable of a data acquisition speed of at least 500 measurements/second per spectral channel is recommended, but, for a large number of applications, speeds of 50 measurements/second per spectral channel are acceptable.
31、 4.1.2 Selection of spectral lines For each analyte to be determined, there exist a number of spectral lines which can be used. Suitable lines shall be selected on the basis of several factors, including the spectral range of the spectrometer used, the analyte mass fraction range, the sensitivity of
32、 the spectral lines and any spectral interference from other elements present in the test specimens. For applications where several of the analytes of interest are major elements in the specimens, special attention shall be paid to the occurrence of self-absorption of certain highly sensitive spectr
33、al lines (so-called resonance lines). Self-absorption causes non-linear calibration curves at high analyte mass fraction levels, and strongly self-absorbed lines should therefore be avoided for the determination of major elements. Suggestions concerning suitable spectral lines are given in Annex B.
34、Spectral lines other than those listed may be used, so long as they have favourable characteristics. 4.1.3 Selection of glow-discharge source type 4.1.3.1 Anode size Most GD-OES instruments on the market are delivered with options to use various anode diameters, 2 mm, 4 mm and 8 mm being the most co
35、mmon. Some older instruments have one anode only, usually 8 mm, while the most commonly used anode in modern instruments is 4 mm. A larger anode requires larger specimens and higher power during analysis; therefore the specimen is heated to a greater extent. On the other hand, a larger anode gives r
36、ise to a plasma of larger volume that emits more light, resulting in lower detection limits (i.e. higher analytical sensitivity). In a large number of applications, the 4 mm anode is a good compromise. However, in surface analysis applications it is rather common to encounter problems of overheating
37、 of the specimens due to e.g. surface layers of poor heat conductivity and/or very thin specimens. In such cases, the smaller 2 mm anode is preferable, even if there is some loss of analytical sensitivity. 4.1.3.2 Type of power supply The glow-discharge source can be either a type powered by a direc
38、t-current (DC) power supply or a radio- frequency (RF) type. The most important difference is that the RF type can sputter both conductive and non- conductive specimens; hence this is the only type that can be used for e.g. polymer coatings and insulating oxide layers. On the other hand, it is techn
39、ically simpler to measure and control the electrical source parameters (voltage, current, power) of a DC type. Several commercially available GD-OES systems can be delivered with the option to switch between DC and RF operation, but RF-only systems are becoming increasingly common. In short, there a
40、re a very large number of applications where DC or RF sources can be used and several where only an RF source can be used. ISO/TS 25138:2010(E) ISO 2010 All rights reserved 34.1.3.3 Mode of operation Both DC and RF sources can be operated in several different modes with respect to the control of the
41、 electrical parameters (current, voltage, power) and the pressure. There are several reasons for this: “historical” reasons (older instruments have simpler but functional power supplies, while the technology has evolved so newer models have more precise and easier-to-operate source control); differe
42、nt manufacturers have chosen different solutions for source control; there are some application-related issues where a particular mode of operation is to be preferred. This Technical Specification gives instructions for optimizing the source parameters based on several available modes of operation.
43、The most important reason for this is to make these instructions comprehensive so as to include several types of instrument. In most applications, there is no major difference between these modes in terms of analytical performance, but there are other differences in terms of practicality and ease of
44、 operation. For instance, a system equipped with active pressure regulation will automatically be adjusted to the same electrical source parameters every time a particular analytical method is used. Without this technology, some manual adjustment of the pressure to achieve the desired electrical sou
45、rce parameters is normally required. NOTE It should be noted in this context that what is known as the emission yield 23forms the basis for calibration and quantification as described in this Technical Specification. The emission yield has been found to vary with the current, the voltage and, to a l
46、esser extent, the pressure 8 . It is impossible in practice to maintain all three parameters constant for all test specimens, due to variations in the electrical characteristics of different materials. In several instrument types, the electrical source parameters (the plasma impedance) can therefore
47、 be maintained constant by means of automatic systems that vary the pressure during analysis. Alternatively, there exist methods to correct for impedance variations by means of empirically derived functions 8 , and this type of correction is implemented in the software of commercially available GD-O
48、ES systems. 5 Adjusting the glow-discharge spectrometer system settings 5.1 General Follow the manufacturers instructions or locally documented procedures for preparing the instrument for use. For the optical system, the most important preparation step is to check that the entrance slit to the spect
49、rometer is correctly adjusted, following the procedure given by the instrument manufacturer. This ensures that the emission intensities are measured on the peaks of the spectral lines for optimum signal-to- background ratio. For further information, see ISO 14707. The most important step in developing a method for a particular application is to optimize the parameters of the glow-discharge source. The source parameters shall be chosen to achieve three aims: a) adequate sputtering of the test specimen, to reduce the an
