1、BSI Standards PublicationBS ISO 17560:2014Surface chemical analysis Secondary-ion massspectrometry Method fordepth profiling of boron insiliconBS ISO 17560:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 17560:2014. Itsupersedes BS ISO 17560:2002 which is
2、withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee CII/60, Surface chemical analysis.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contr
3、act. Users are responsible for its correctapplication. The British Standards Institution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 85636 5ICS 71.040.40Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the author
4、ity of theStandards Policy and Strategy Committee on 30 September 2014.Amendments issued since publicationDate Text affectedBS ISO 17560:2014 ISO 2014Surface chemical analysis Secondary-ion mass spectrometry Method for depth profiling of boron in siliconAnalyse chimique des surfaces Spectromtrie de
5、masse des ions secondaires Dosage du bore dans le silicium par profilage dpaisseurINTERNATIONAL STANDARDISO17560Second edition2014-09-15Reference numberISO 17560:2014(E)BS ISO 17560:2014ISO 17560:2014(E)ii ISO 2014 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2014All rights reserved. Unless o
6、therwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the addre
7、ss below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 17560:2014ISO 17560:2014(E) ISO 2014 All rights reserved iiiContents PageF
8、oreword ivIntroduction v1 Scope . 12 Normative reference . 13 Symbols and abbreviations . 14 Principle 25 Reference materials 25.1 Reference materials for determination of relative-sensitivity factors 25.2 Reference materials for calibration of depth scale 26 Apparatus . 26.1 Secondary-ion mass spec
9、trometer 26.2 Stylus profilometer 26.3 Optical interferometer 37 Specimen . 38 Procedure. 38.1 Adjustment of secondary-ion mass spectrometer . 38.2 Optimizing the secondary-ion mass spectrometer settings 38.3 Specimen introduction . 48.4 Detected ions 48.5 Measurement of test specimen . 48.6 Calibra
10、tion 59 Expression of results 610 Test report . 7Annex A (informative) Statistical report of stylus profilometry measurements 8Bibliography .10BS ISO 17560:2014ISO 17560:2014(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS
11、O 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, gove
12、rnmental 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 mainten
13、ance 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).Attenti
14、on 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 a
15、nd/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 on the meaning of ISO specific terms and expressions related to conformity
16、assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 201, Surface chemical analysis, Subcommittee SC 6, Secondary ion mas
17、s spectrometry.Annex A of this International Standard is for information only.This second edition cancels and replaces the first edition (ISO 17560:2002), which has been technically revised. The revision also includes editorial correction.iv ISO 2014 All rights reservedBS ISO 17560:2014ISO 17560:201
18、4(E)IntroductionThis International Standard was prepared for the quantitative 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
19、for the determination of boron in silicon has been established as an International Standard, ISO 14237. Thus, the calibration of boron atomic concentration is performed by following ISO 14237.This International Standard describes standard procedures for depth profiling of boron in single-crystal, po
20、ly-crystal, or amorphous silicon using SIMS and for depth scale calibration using stylus profilometry or optical interferometry. ISO 2014 All rights reserved vBS ISO 17560:2014BS ISO 17560:2014Surface chemical analysis Secondary-ion mass spectrometry Method for depth profiling of boron in silicon1 S
21、copeThis 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 stylus profilometry or optical interferometry for depth scale calibration. This method is applicable to single
22、-crystal, poly-crystal, or amorphous silicon specimens with boron atomic concentrations between 1 1016atoms/cm3and 1 1020atoms/cm3, and to crater depths of 50 nm or deeper.2 Normative referenceThe following documents, in whole or in part, are normatively referenced in this document and are indispens
23、able for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 14237:2010, Surface chemical analysis Secondary-ion mass spectrometry Determination of boron atomic concentrati
24、on in silicon using uniformly doped materials3 Symbols and abbreviationsCitotal boron atomic concentration in measurement cycle i, expressed in atoms per cubic centi-metre (atoms/cm3)Ci10atomic concentration of the boron isotope with mass number 10 in measurement cycle i, expressed in atoms per cubi
25、c centimeter (atoms/cm3)Ci11atomic concentration of the boron isotope with mass number 11 in measurement cycle i, expressed in atoms per cubic centimeter (atoms/cm3)didepth measured in measurement cycle i, expressed in micrometres (m) or nanometers (nm)dtcrater depth, expressed in micrometres (m) or
26、 nanometres (nm)Ii10ion intensity of the boron isotope with mass number 10 in measurement cycle i, expressed in counts per second (counts/s)Ii11ion intensity of the boron isotope with mass number 11 in measurement cycle i, expressed in counts per second (counts/s)IiSiion intensity of silicon matrix
27、in measurement cycle i, expressed in counts per second (counts/s)Ji10boron to silicon ion intensity ratio for the boron isotope with mass number 10 in measure-ment cycle iJi11boron to silicon ion intensity ratio for the boron isotope with mass number 11 in measure-ment cycle iJBG10mean background bo
28、ron to silicon ion intensity ratio for the boron isotope with mass number 10 in measurement cycle iINTERNATIONAL STANDARD ISO 17560:2014(E) ISO 2014 All rights reserved 1BS ISO 17560:2014ISO 17560:2014(E)JBG11mean background boron to silicon ion intensity ratio for the boron isotope with mass number
29、 11 in measurement cycle iN total number of measurement cyclesT total measurement time, expressed in seconds (s)tiBstarting time of boron-ion acquisition in measurement cycle i, expressed in seconds (s)tiBduration of boron-ion acquisition in each measurement cycle, expressed in seconds (s) mass disc
30、rimination correction factor wavelength of the light for optical interferometry, expressed in micrometres (m) or nanome-tres (nm)RSFworkworking relative-sensitivity factorSIMS secondary-ion mass spectrometry4 PrincipleAn oxygen-ion beam or caesium-ion beam is scanned over the specimen surface and th
31、e 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 the ion beam is measured by stylu
32、s profilometry or optical interferometry for depth scale calibration.NOTE Optical interferometry is generally applicable to crater depths in the range from 0,5 m to 5 m.5 Reference materials5.1 Reference materials for determination of relative-sensitivity factorsThe reference materials should be as
33、specified in ISO 14237:2010, Clause 4.5.2 Reference materials for calibration of depth scaleFor stylus profilometry calibration, certified reference materials or reference materials, which are traceable to certified reference materials, shall be used.6 Apparatus6.1 Secondary-ion mass spectrometerThe
34、 apparatus should be as specified in ISO 14237:2010, Clause 5.6.2 Stylus profilometerUse a stylus profilometer with the sensitivity and tip shapes suitable for the crater shapes to be measured.2 ISO 2014 All rights reservedBS ISO 17560:2014ISO 17560:2014(E)6.3 Optical interferometerUse an optical in
35、terferometer with the sensitivity and functions suitable for the crater shapes to be measured.7 SpecimenThe specimen shall be cut to an appropriate size for analysis and degreased and washed if necessary.NOTE The accuracy of crater depth measurement is largely influenced by surface roughness. A mirr
36、or-polished wafer is preferable when accurate determination of the depth scale is necessary.8 Procedure8.1 Adjustment of secondary-ion mass spectrometer8.1.1 For oxygen-ion beam use, see Table 1. For caesium-ion beam use, see Table 2. Other conditions not shown here shall be set in accordance with t
37、he manufacturers instructions or a local documented procedure.Table 1 Measurement conditions for oxygen-ion beamPrimary-ion speciesSecondary-ion polarityPrimary-ion scan regionAnalysed regionO2+Positive three times the linear dimension of the ana-lysed region in all directionsCentred in the primary-
38、ion scan regionTable 2 Measurement conditions for caesium-ion beamPrimary-ion speciesSecondary-ion polarityPrimary-ion scan regionAnalysed regionCs+Negative three times the linear dimension of the ana-lysed region in all directionsCentred in the primary-ion scan region8.1.2 For the primary-ion beam,
39、 the beam current and scan region can vary from specimen to specimen (see 8.5.2). However, when oxygen gas is introduced into the chamber 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.
40、2 Optimizing the secondary-ion mass spectrometer settings8.2.1 Set the required instrument parameters and align the ion optics in accordance with the manufacturers instructions or a local documented procedure.8.2.2 Ensure the stability of the primary-ion current and the mass spectrometer in accordan
41、ce with the manufacturers instructions or a local documented procedure.8.2.3 For a mass spectrometer whose transmission can be varied, use the same transmission for the measurements on both reference materials and test specimens. ISO 2014 All rights reserved 3BS ISO 17560:2014ISO 17560:2014(E)8.3 Sp
42、ecimen introductionImmediately prior to introduction of the specimens into the SIMS apparatus, dust particles shall be removed from the surfaces with a pressurized duster. After introducing the specimens into the analysis chamber, analysis shall not start until the pressure has recovered to the norm
43、al value recommended by the manufacturer or a local documented procedure.NOTE 1 Residual gases in the analysis chamber can produce a 10B28Si1Hbackground signal which interferes with the 11B28Sisignal. This background can be reduced by improving the vacuum in the analysis chamber.NOTE 2 With an amorp
44、hous-silicon specimen, the background described in Note 1 will be present because of hydrogen in the specimen.8.4 Detected ions8.4.1 When an oxygen-ion beam is used, both 10B+and 11B+shall be detected. When a caesium-ion beam is used, both 10B28Siand 11B28Sishall be detected.8.4.2 The ion species of
45、 silicon which has the appropriate ion intensity shall be detected, following the manufacturers instructions or a local documented procedure.If the instrument has an electrometer detection mode, it is recommended that 28Si+be detected as the reference ion of B+using the electrometer. For BSidetectio
46、n, Si2is preferable as the reference ion. For the pulse-counting mode, the instantaneous silicon-ion count rate should be less than 1 105counts/s.NOTE When an amorphous-silicon specimen is analysed, note that Si-H cluster ions can interfere with the 29Si-ion, 30Si-ion, and their molecular-ion signal
47、s. Therefore, the 28Si-ion or its molecular ions (e.g. 28Si+, 28Si2+) are preferable as the matrix ion.8.5 Measurement of test specimen8.5.1 Measurements shall be made in the central region of the specimen holder window.8.5.2 The primary-ion beam current and the beam scan area shall be chosen so tha
48、t sufficient data points are obtained to record the details of the profile. It is useful to measure a test profile to determine these conditions. When the boron-ion intensity of the specimen is high (e.g. 1 105counts/s), care shall be taken to avoid unacceptable nonlinearity in the detector response
49、 due to pulse overlap. If the boron-ion intensity is higher than 5 105counts/s 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).In an ion microscope type instrument, ion intensities could be reduced by using a small field-limiting aperture. However, this would not reduce the instantaneous count rate from the analysed region. The overall transmission should be changed instead of using a s
