ASTM E1438-11(2019)
(Guide)Standard Guide for Measuring Widths of Interfaces in Sputter Depth Profiling Using SIMS
Standard Guide for Measuring Widths of Interfaces in Sputter Depth Profiling Using SIMS
SIGNIFICANCE AND USE
5.1 Although it would be desirable to measure the extent of profile distortion in any unknown sample by using a standard sample and this guide, measurements of interface width (profile distortion) can be unique to every sample composition (1, 2).4 This guide, describes a method that determines the unique width of a particular interface for the chosen set of operating conditions. It is intended to provide a method for checking on proper or consistent, or both, instrument performance. Periodic analysis of the same sample followed by a measurement of the interface width, in accordance with this guide, will provide these checks.
5.2 The procedure described in this guide is adaptable to any layered sample with an interface between layers in which a nominated element is present in one layer and absent from the other. It has been shown that for SIMS in particular (3, 4) and for surface analysis in general (5, 6), only rigorous calibration methods can determine accurate interface widths. Such procedures are prohibitively time-consuming. Therefore the interface width measurement obtained using the procedure described in this guide may contain significant systematic error (7). Therefore, this measure of interface width may have no relation to similar measures made with other methods. However, this does not diminish its use as a check on proper or consistent instrument performance, or both.
5.3 This guide can be used for both elemental and molecular depth profiles, provided that the materials have constant sputter rates throughout the depth of the overlayer, and minimal interlayer mixing is occurring. For more detailed information regarding measurements of interface widths during organic depth profiling, please see Mahoney (8).
SCOPE
1.1 This guide provides the SIMS analyst with a method for determining the width of interfaces from SIMS sputtering data obtained from analyses of layered specimens (both organic and inorganic). This guide does not apply to data obtained from analyses of specimens with thin markers or specimens without interfaces such as ion-implanted specimens.
1.2 This guide does not describe methods for the optimization of interface width or the optimization of depth resolution.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:E1438 −11 (Reapproved 2019)
Standard Guide for
Measuring Widths of Interfaces in Sputter Depth Profiling
Using SIMS
This standard is issued under the fixed designation E1438; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Summary of Guide
1.1 This guide provides the SIMS analyst with a method for
4.1 This guide will allow interface widths to be calculated
determining the width of interfaces from SIMS sputtering data
fromplotsofSIMSsecondaryionintensityversustimethatare
obtained from analyses of layered specimens (both organic and
acquired during sputtering of layered specimens. It assumes
inorganic). This guide does not apply to data obtained from
that a primary ion beam with a stable current density is being
analyses of specimens with thin markers or specimens without
used. Briefly, these plots are obtained in the following fashion:
interfaces such as ion-implanted specimens.
an ion beam of a particular ion species, ion energy, and angle
of incidence is used to bombard a sample.The beam is rastered
1.2 This guide does not describe methods for the optimiza-
or defocused so as to attempt to produce uniform current
tion of interface width or the optimization of depth resolution.
density in the analyzed area, that is defined by means of
1.3 This standard does not purport to address all of the
mechanical or electronic gating. The intensity of one or more
safety concerns, if any, associated with its use. It is the
secondary ions is monitored with respect to time as sputtering
responsibility of the user of this standard to establish appro-
continues.
priate safety, health, and environmental practices and deter-
4.2 The interface width is then determined from the second-
mine the applicability of regulatory limitations prior to use.
ary ion intensity versus time data according to an arithmetic
1.4 This international standard was developed in accor-
model described in the Procedure section. A measurement of
dance with internationally recognized principles on standard-
the thickness of the layer overlying the interface is required.
ization established in the Decision on Principles for the
This measurement may be performed by another analytical
Development of International Standards, Guides and Recom-
technique.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
5. Significance and Use
2. Referenced Documents
5.1 Although it would be desirable to measure the extent of
2.1 ASTM Standards: profile distortion in any unknown sample by using a standard
E673 Terminology Relating to SurfaceAnalysis (Withdrawn sample and this guide, measurements of interface width (pro-
2012) file distortion) can be unique to every sample composition (1,
2). This guide, describes a method that determines the unique
3. Terminology width of a particular interface for the chosen set of operating
conditions. It is intended to provide a method for checking on
3.1 Definitions:
proper or consistent, or both, instrument performance. Periodic
3.1.1 SeeTerminology E673 for definitions of terms used in
analysis of the same sample followed by a measurement of the
SIMS.
interface width, in accordance with this guide, will provide
these checks.
5.2 The procedure described in this guide is adaptable to
This guide is under the jurisdiction of ASTM Committee E42 on Surface
any layered sample with an interface between layers in which
Analysis and is the direct responsibility of Subcommittee E42.06 on SIMS.
Current edition approved Nov. 1, 2019. Published November 2019. Originally
anominatedelementispresentinonelayerandabsentfromthe
approved in 1991. Last previous edition approved in 2011 as E1438 – 11. DOI:
other. It has been shown that for SIMS in particular (3, 4) and
10.1520/E1438-11R19.
for surface analysis in general (5, 6), only rigorous calibration
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3 4
The last approved version of this historical standard is referenced on The boldface numbers given in parentheses refer to a list of references at the
www.astm.org. end of this guide.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1438−11 (2019)
methods can determine accurate interface widths. Such proce-
dures are prohibitively time-consuming. Therefore the inter-
face width measurement obtained using the procedure de-
scribed in this guide may contain significant systematic error
(7). Therefore, this measure of interface width may have no
relation to similar measures made with other methods.
However, this does not diminish its use as a check on proper or
consistent instrument performance, or both.
5.3 Thisguidecanbeusedforbothelementalandmolecular
depthprofiles,providedthatthematerialshaveconstantsputter
rates throughout the depth of the overlayer, and minimal
interlayer mixing is occurring. For more detailed information
regarding measurements of interface widths during organic
depth profiling, please see Mahoney (8).
6. Apparatus
FIG. 1 Measurement of Interface Width, ∆z, from a Plot of SIMS
6.1 The procedure described in this guide can be used to
Intensity Versus Ion Bombardment Time
determine an interface width from data obtained with virtually
any SIMS instrument.
6.2 Use of the interface width measurement from a layered
specimen as a check on proper or consistent instrument
7.1.2 The th
...
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