ASTM E1438-91(1996)

Standard Guide for Measuring Widths of Interfaces in Sputter Depth Profiling Using SIMS

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. 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 problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 14-Sep-1991
• Technical Committee: E42 - Surface Analysis
• Drafting Committee: E42.06 - SIMS

Relations

• Replaced By: ASTM E1438-91(2001) - Standard Guide for Measuring Widths of Interfaces in Sputter Depth Profiling Using SIMS
• Effective Date: 15-Sep-1991

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 1438 – 91 (Reapproved 1996)
Standard Guide for
Measuring Widths of Interfaces in Sputter Depth Profiling
Using SIMS
This standard is issued under the fixed designation E 1438; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 4.2 The interface width is then determined from the second-
ary ion intensity versus time data according to an arithmetic
1.1 This guide provides the SIMS analyst with a method for
model described in the Procedure section. A measurement of
determining the width of interfaces from SIMS sputtering data
the thickness of the layer overlying the interface is required.
obtained from analyses of layered specimens. This guide does
This measurement may be performed by another analytical
not apply to data obtained from analyses of specimens with
technique.
thin markers or specimens without interfaces such as ion-
implanted specimens.
5. Significance and Use
1.2 This guide does not describe methods for the optimiza-
5.1 Although it would be desirable to measure the extent of
tion of interface width or the optimization of depth resolution.
profile distortion in any unknown sample by using a standard
1.3 This standard does not purport to address all of the
sample and this guide, measurements of interface width (pro-
safety concerns, if any, associated with its use. It is the
file distortion) can be unique to every sample composition (1,
responsibility of the user of this standard to establish appro-
2, 3). This guide, that describes a method that determines the
priate safety and health practices and determine the applica-
unique width of a particular interface, is primarily intended to
bility of regulatory limitations prior to use.
provide a method for checking on proper or consistent instru-
2. Referenced Documents ment performance, or both. Periodic analysis of the same
sample followed by a measurement of the interface width, in
2.1 ASTM Standards:
accordance with this guide, will provide these checks.
E 673 Terminology Relating to Surface Analysis
5.2 The procedure described in this guide is adaptable to
3. Terminology
any layered sample with an interface between layers of
differing compositions. It has been shown that for SIMS in
3.1 Definitions:
particular (4, 5) and for surface analysis in general (6, 7), only
3.1.1 See Terminology E 673 for definitions of terms used in
rigorous calibration methods can determine accurate interface
SIMS.
widths. Such procedures are prohibitively time-consuming.
4. Summary of Guide
Therefore the interface width measurement obtained using the
procedure described in this guide may contain significant
4.1 This guide will allow interface widths to be calculated
systematic error (8). However, this does not diminish its use as
from plots of SIMS secondary ion intensity versus time that are
a check on proper or consistent instrument performance, or
acquired during sputtering of layered specimens. It assumes
both.
that a primary ion beam with a stable current density is being
used. Briefly, these plots are obtained in the following fashion:
6. Apparatus
an ion beam of a particular ion species, ion energy, and angle
6.1 The procedure described in this guide can be used to
of incidence is used to bombard a sample. The beam is rastered
determine an interface width from data obtained with virtually
or defocused so as to attempt to produce uniform current
any SIMS instrument.
density in the analyzed area, that is defined by means of
6.2 Use of the interface width measurement from a layered
mechanical or electronic gating. The intensity of one or more
specimen as a check on proper or consistent instrument
secondary ions is monitored with respect to time as sputtering
performance, or both, does not assume that the sample of
continues.
interest contains no interface roughness. Rather, it assumes that
the interface roughness is consistent from one analyzed area to
This guide is under the jurisdiction of ASTM Committee E-42 on Surface
Analysis and is the direct responsibility of Subcommittee E42.06 on SIMS.
Current edition approved Sept. 15, 1991. Published November
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