ASTM E1505-92(1996)

Standard Guide for Determining SIMS Relative Sensitivity Factors from Ion Implanted External Standards

SCOPE
1.1 The purpose of this guide is to provide the secondary ion mass spectrometry (SIMS) analyst with two procedures for determining relative sensitivity factors (RSFs) from ion implanted external standards. This guide may be used for obtaining the RSFs of trace elements (
1.2 This guide does not describe procedures for obtaining RSFs for major elements (>1 atomic %). In addition, this guide does not describe procedures for obtaining RSFs from implants in heterogeneous (either laterally or in-depth) specimens.
1.3 The values stated in SI units are to be regarded as the standard.
1.4 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 14-Nov-1992
• Technical Committee: E42 - Surface Analysis
• Drafting Committee: E42.06 - SIMS

Relations

• Replaced By: ASTM E1505-92(2001) - Standard Guide for Determining SIMS Relative Sensitivity Factors from Ion Implanted External Standards (Withdrawn 2010)
• Effective Date: 15-Nov-1992

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NOTICE: This standard has either been superseded and replaced by a new version or discontinued.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 1505 – 92 (Reapproved 1996)
Standard Guide for
Determining SIMS Relative Sensitivity Factors from Ion
Implanted External Standards
This standard is issued under the fixed designation E 1505; 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 ary ions associated with the implanted element of interest and
a reference element (typically, a major element in the specimen
1.1 The purpose of this guide is to provide the secondary ion
matrix, which is distributed homogeneously in the specimen at
mass spectrometry (SIMS) analyst with two procedures for
a known concentration) are monitored with respect to time
determining relative sensitivity factors (RSFs) from ion im-
during the ion sputtering.
planted external standards. This guide may be used for obtain-
4.2 An RSF for a given analyte ion, A, and a given reference
ing the RSFs of trace elements (<1 atomic %) in homogeneous
ion, R, is equal to the ratio of their respective useful ion yields,
(chemically and structurally) specimens. This guide is useful
−1
t ·t , where t equals the number of ions detected divided by
A R
for all SIMS instruments.
the number of corresponding atoms sputtered (1-3). An RSF is
1.2 This guide does not describe procedures for obtaining
determined from the secondary ion intensity versus time data
RSFs for major elements (>1 atomic %). In addition, this guide
obtained from implanted standards using one of two arithmetic
does not describe procedures for obtaining RSFs from implants
models described in the procedure (Section 7) of this guide. A
in heterogeneous (either laterally or in-depth) specimens.
measure of final crater depth is required for RSF determination.
1.3 The values stated in SI units are to be regarded as the
This measurement may be performed by another analytical
standard.
technique (see Section 7).
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
5. Significance and Use
responsibility of the user of this standard to establish appro-
5.1 The quantification of trace element compositions in
priate safety and health practices and determine the applica-
homogeneous matrices from first principles requires (1) knowl-
bility of regulatory limitations prior to use.
edge of the factors influencing ion and sputtering yields and (2)
2. Referenced Documents understanding of how instrumental parameters influence these
yields (1-3). This information is difficult to obtain. Therefore,
2.1 ASTM Standards:
SIMS operators commonly use external standards to determine
E 673 Terminology Relating to Surface Analysis
RSFs. These RSFs are then used to quantify the composition of
3. Terminology trace elements in the specimen of interest through the applica-
tion of the following equation to each data point of the depth
3.1 Definitions—See Terminology E 673 for definitions of
profile of interest (1-3).
terms used in SIMS.
C 5 I · C · I · RSF · N! (1)
~
A A R R
4. Summary of Practice
where:
4.1 This guide will allow calculation of the RSFs of trace
−3
C and C 5 concentrations (atoms-cm ) of the analyte
elements from plots of SIMS secondary ion intensity (counts/s) A R
and reference elements, respectively;
versus time (s) that are acquired during the sputtering of ion
I and I 5 intensities (counts/s) obtained from the ana-
implanted external standards. Briefly, these plots are obtained a R
lyte and reference ions, respectively; and
in the following manner: an ion beam of a particular ion
N 5 natural abundance (expressed as a fraction)
species, ion energy, and angle of incidence is used to bombard
of the analyte isotope being examined.
an ion implanted external standard. The beam is rastered or
5.2 The most common method of creating external stan-
defocussed in order to attempt to produce uniform current
dards is to use an ion accelerator to homogeneously implant a
density in the analyzed area, which is defined by means of
known dose of ions of a particular elemental isotope into a
mechanical or electronic gating. The intensities of the second-
specimen matrix that matches the specimen of interest (4). The
implanted ion depth distribution is near-Gaussian (see Fig. 1)
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 Nov. 15, 1992. Published January 1993. The boldface numbers in parentheses refer to the list of references at the end of
Annual Book of ASTM Standards, Vol 03.06. this guide.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
E 1505
s5 measured standard deviation of the implant distribu-
tion (cm), which equals half the peak width at 0.606 of
the maximum intensity.
Once C has been measured, t can be determined using
A,max A
the following relationship:
t 5 I · C · A · z (3)
~ !
A A,max A,max o
where:
I 5 intensity at the peak,
A,max
A 5 area (cm ) analyzed, and
o
z 5 sputtering rate (cm/s).
Similarly, t can be determined using the following relation-
R
ship:
t 5 I · ~C · A · z! (4)
R R,avg R o
where:
I 5 average intensity obtained from the reference ion.
R,avg
FIG. 1 Parameter for Implant Quantification
From these two expressions for the useful ion yields, the
following expression for determining RSFs is obtained:
21 21
RSF5t · t 5 I · C · ~I · C ! (5)
A R A,max R R,avg A,max
and is therefore distinguished readily from background signal
With the exception of C , all of these parameters are
intensities. Elemental quantification performed using RSFs A,max
either known or can be determined directly from the depth
obtained from implan
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