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1、BRITISH STANDARD BS ISO 17560:2002 Surface chemical analysis Secondary-ion mass spectrometry Method for depth profiling of boron in silicon ICS 71.040.40 ? Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:12:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 17560:2002 This British Standa
2、rd, having been prepared under the direction of the Materials and Chemicals Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 28 August 2002 BSI 28 August 2002 ISBN 0 580 40299 1 National foreword This British Standard reproduce
3、s verbatim ISO 17560:2002 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee CII/60, Surface chemical analysis, which has the responsibility to: A list of organizations represented on this committee can be obtained on request t
4、o its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalog
5、ue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the
6、 text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front
7、 cover, an inside front cover, the ISO title page, pages ii to v, a blank page, pages 1 to 10, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. DateComments Licensed Copy
8、: sheffieldun sheffieldun, na, Mon Nov 27 04:12:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI INTERNATIONAL STANDARD ISO 17560 First edition 2002-07-15 Reference number ISO 17560:2002(E) Surface chemical analysis Secondary-ion mass spectrometry Method for depth profiling of boron in silicon Analyse
9、chimique des surfaces Spectromtrie de masse des ions secondaires Dosage du bore dans le silicium par profilage dpaisseur BS ISO 17560:2002 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:12:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii BS ISO 17560:2002 Licensed Copy: sheffieldun sheffi
10、eldun, na, Mon Nov 27 04:12:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iii Contents Page 1Scope . 1 2Normative reference . 1 3Symbols and abbreviated terms . 1 4Principle 2 5Reference materials . 2 6Apparatus . 2 7Specimen 3 8Procedures . 3 9Expression of results 6 10Test report 6 Annex AStatisti
11、cal report of stylus profilometry measurements. 8 Bibliography. 10 BS ISO 17560:2002 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:12:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national s
12、tandards 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
13、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. International Standards are drafted in accordance with the rules gi
14、ven in the ISO/IEC Directives, Part 3. 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. Attention is drawn to the possibil
15、ity that some of the elements of this International Standard may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. International Standard ISO 17560 was prepared by Technical Committee ISO/TC 201, Surface chemical analysis, Subcommittee
16、SC 6, Secondary ion mass spectrometry. Annex A of this International Standard is for information only. BS ISO 17560:2002 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:12:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI v Introduction This International Standard was prepared for the quantita
17、tive depth profiling of boron in silicon by secondary-ion mass spectrometry (SIMS). For quantitative depth profiling, calibration is necessary both for the concentration and the depth scales of the profile measured. A procedure for the determination of boron in silicon has been established as an Int
18、ernational Standard, ISO 14237. Thus, the calibration of boron atomic concentration is performed by following ISO 14237. In this International Standard, standard procedures are described for depth profiling of boron in single-crystal, poly-crystal or amorphous silicon using SIMS and for depth scale
19、calibration using stylus profilometry or optical interferometry. BS ISO 17560:2002 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:12:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:12:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 1 S
20、urface chemical analysis Secondary-ion mass spectrometry Method for depth profiling of boron in silicon 1Scope This International Standard specifies a secondary-ion mass spectrometric method using magnetic-sector or quadrupole mass spectrometers for depth profiling of boron in silicon, and using sty
21、lus profilometry or optical interferometry for depth scale calibration. This method is applicable to single-crystal, poly-crystal or amorphous- silicon specimens with boron atomic concentrations between and , and to crater depths of or deeper. 2Normative reference The following normative document co
22、ntains provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, this publication do not apply. However, parties to agreements based on this International Standard are encouraged to investi
23、gate the possibility of applying the most recent edition of the normative document indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 14237:2000, Surface
24、chemical analysis Secondary-ion mass spectrometry Determination of boron atomic concentration in silicon using uniformly doped materials 3Symbols and abbreviated terms total boron atomic concentration in measurement cycle , expressed in atoms per cubic centimetre () atomic concentration of the boron
25、 isotope with mass number 10 in measurement cycle , expressed in atoms per cubic centimetre () atomic concentration of the boron isotope with mass number 11 in measurement cycle , expressed in atoms per cubic centimetre () depth measured in measurement cycle , expressed in micrometres () or nanometr
26、es () crater depth, expressed in micrometres () or nanometres () ion intensity of the boron isotope with mass number 10 in measurement cycle ion intensity of the boron isotope with mass number 11 in measurement cycle ion intensity of silicon matrix in measurement cycle boron to silicon ion intensity
27、 ratio for the boron isotope with mass number 10 in measurement cycle boron to silicon ion intensity ratio for the boron isotope with mass number 11 in measurement cycle mean background boron to silicon ion intensity ratio for the boron isotope with mass number 10 in measurement cycle 11016atoms/cm3
28、11020atoms/cm3 50 nm Cii atoms/cm3 C10 i i atoms/cm3 C11 i i atoms/cm3 diimnm dtmnm I10 i i I11 i i ISi i i J10 i i J11 i i J10 BG i BS ISO 17560:2002 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:12:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 2 mean background boron to silicon ion int
29、ensity ratio for the boron isotope with mass number 11 in measurement cycle total number of measurement cycles total measurement time, expressed in seconds ( ) starting time of boron-ion acquisition in measurement cycle , expressed in seconds ( ) duration of boron-ion acquisition in each measurement
30、 cycle, expressed in seconds ( ) mass discrimination correction factor wavelength of the light for optical interferometry, expressed in micrometres () or nanometres () working relative-sensitivity factor SIMSsecondary-ion mass spectrometry 4Principle An oxygen-ion beam or caesium-ion beam is scanned
31、 over the specimen surface and the emitted secondary ions of boron and silicon from a gated region within the area scanned by the ion beam are detected and mass-analysed. The intensities of these mass-analysed signals are monitored as a function of sputtering time. The depth of the crater formed by
32、the ion beam is measured by stylus profilometry or optical interferometry for depth scale calibration. NOTEOptical interferometry is generally applicable to crater depths in the range from to . 5Reference materials 5.1Reference materials for determination of relative-sensitivity factors Follow claus
33、e 4 of ISO 14237:2000. 5.2Reference materials for calibration of depth scale For stylus profilometry calibration, certified reference materials or reference materials which are traceable to certified reference materials shall be used. 6Apparatus 6.1Secondary-ion mass spectrometer As specified in cla
34、use 5 of ISO 14237:2000. 6.2Stylus profilometer Use a stylus profilometer with a sensitivity and tip shapes suitable for the crater shapes to be measured. 6.3Optical interferometer Use an optical interferometer with a sensitivity and functions suitable for the crater shapes to be measured. J11 BG i
35、N Ts tB i is tBs mnm RSFwork 0,5m5m BS ISO 17560:2002 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:12:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 3 7Specimen The specimen shall be cut to an appropriate size for analysis and degreased and washed if necessary. NOTEThe accuracy of crater
36、 depth measurement is largely influenced by surface roughness. A mirror-polished wafer is preferable when accurate determination of the depth scale is necessary. 8Procedures 8.1Adjustment of secondary-ion mass spectrometer 8.1.1For oxygen-ion beam use, see Table 1. For caesium-ion beam use, see Tabl
37、e 2. Other conditions not shown here shall be set in accordance with the manufacturers instructions or a local documented procedure. 8.1.2For the primary-ion beam, the beam current and scan region can be varied from specimen to specimen (see 8.5.2). However, when oxygen gas is introduced into the ch
38、amber during oxygen-beam irradiation, the oxygen pressure and all the primary-ion beam irradiation conditions shall be the same for the measurements on all specimens. 8.2Optimizing the secondary-ion mass spectrometer settings 8.2.1Set the required instrument parameters and align the ion optics in ac
39、cordance with the manufacturers instructions or a local documented procedure. 8.2.2Ensure the stability of the primary-ion current and the mass spectrometer in accordance with the manufacturers instructions or a local documented procedure. 8.2.3For a mass spectrometer whose transmission can be varie
40、d, use the same transmission for the measurements on both reference materials and test specimens. Table 1 Measurement conditions for oxygen-ion beam Primary-ion speciesO2+ Secondary-ion polarityPositive Primary-ion scan region three times the linear dimension of the analysed region in all directions
41、 Analysed regionCentred in the primary-ion scan region Table 2 Measurement conditions for caesium-ion beam Primary-ion speciesCs+ Secondary-ion polarityNegative Primary-ion scan region three times the linear dimension of the analysed region in all directions Analysed regionCentred in the primary-ion
42、 scan region BS ISO 17560:2002 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 04:12:09 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 4 8.3Specimen introduction Immediately prior to introduction of the specimens into the SIMS apparatus, dust particles shall be removed from the surfaces with a pr
43、essurized duster. After introducing the specimens into the analysis chamber, analysis shall not start until the pressure has recovered to the normal value recommended by the manufacturer or a local documented procedure. NOTE 1Residual gases in the analysis chamber can produce a 10B28Si1H background
44、signal which interferes with the 11B28Si signal. This background can be reduced by improving the vacuum in the analysis chamber. NOTE 2With an amorphous-silicon specimen, it should be noted that the above background will be present because of hydrogen in the specimen. 8.4Detected ions 8.4.1When an o
45、xygen-ion beam is used, both 10B+ and 11B+ shall be detected. When a caesium-ion beam is used, both 10B28Si and 11B28Si shall be detected. 8.4.2The ion species of silicon which has an appropriate ion intensity shall be detected, following the manufacturers instructions or a local documented procedur
46、e. NOTE 1If the instrument has an electrometer detection mode, it is recommended that 28Si+ be detected as the reference ion of B+ using the electrometer. For BSi detection, Si2 is preferable as the reference ion. For the pulse-counting mode, the instantaneous silicon-ion count rate should be less t
47、han . NOTE 2When an amorphous-silicon specimen is analysed, it should be noted that Si-H cluster ions can interfere with the 29Si-ion, 30Si-ion and their molecular-ion signals. Therefore, the 28Si-ion or its molecular ions (e.g. 28Si+, 28Si2+) are preferable as the matrix ion. 8.5Measurement of test
48、 specimen 8.5.1Measurements shall be made in the central region of the specimen holder window. 8.5.2The primary-ion beam current and the beam scan area shall be chosen so that sufficient data points are obtained to record the details of the profile. It is useful to measure a test profile to determin
49、e these conditions. When the boron-ion intensity of the specimen is high (e.g. ), care shall be taken so as not to saturate the detector. If the boron-ion intensity is higher than in the analysed area (i.e. gated area), the primary-ion current shall be reduced or, alternatively, the transmission of the mass spectrometer shall be reduced (see 8.2.3). NOTE 1In an ion microscope type instrument, ion intensities could be reduced by using a small field-limiting aperture. Ho