SIMS-EDX system for a
standard-free analysis
Yu. Kudriavtsev, R.Asomoza
Sección Electrónica del Estado Solido,
Departamento Ingeniería Eléctrica,
CINVESTAV-IPN,
Av. IPN #2508, México, DF 07360, México
yuriyk@cinvestav.mx
Introduction
SIMS as any other technique has advantage as well as
weak points. The most important disadvantage is poor
quantification of SIMS data: by using implanted standards
quantification can be done with an experimental error of
around ±20%. SIMS analysis of main elements (the
concentration range of 1%-100%) cannot be quantified by
SIMS using implanted standards; a special calibration
procedure should be performed, because of non-linear
dependence between concentration of the element of
interest and experimental secondary ion current, monitored
for it.
Energy dispersive X-ray spectroscopy ideally complements
SIMS, because of standard free quantitative analysis of
most of the elements with the concentration from 0.01
atomic % to 100 atomic %.
General idea:
Utilize an Electron Gun of any SIMS instrument, used
typically for charge compensation, to excite
characteristic X-Ray emission from analyzed sample
to realize Energy Dispersive X-ray spectroscopy
method with the SIMS instrument.
Installation of EDD at ims-6f instrument
Si crystal of EDD
Primary ion trap
EDX detector:
Exterior view
A modified Strip: the closed window protect EDD in the
SIMS mode
Application of EDX-SIMS instrument:
I. Semiconductors
1. Quantitative analysis of solid solutions: bulk, thick
films, thin films. See Poster Section: Tue-pos-43
2. Calibration of SIMS (RSFs) for main element analysis
in complex materials.
3. Shallow junction analysis (LEXES “inside“).
II. Metals and alloys:
Quantitative analysis of bulk, thick films and thin films.
III. Glass (including natural), ceramics, minerals, etc.
Quantitative analysis of bulk, thick films and thin films.
X-ray spectrum
of obsidian
Two different strategies:
I. Perform a quantification of main elements by EDX ,
then analyze dopants and contamination by SIMS
MBE grown 1 micron epi-layer of Al0.2Ga0.8N: EDX
spectrum and SIMS depth profile
6042105
1E23
133Cs14N
133Cs16O
133Cs24Mg
133Cs27Al
133Cs69Ga
133Cs21H
1E22
Atoms/cm
3
1E21
1E20
1E19
1E18
0
200
400
Time, sec
600
800
II. “Internal calibration” of SIMS
1E23
1E22
EDX
Concentration, atoms/cm
3
1E21
1E20
1E19
1E18
1E17
1E16
1E15
1E14
SIMS
Elemento
Ti*
Al*
V
Mo
Zr
Fe
Si
Concentración
, % atómicos
83.2
9.2
4.5
3.0
0.1
0.1
0.1
EDX spectrum and found composition of Ti allow
1E25
RSF, atoms/cm
3
1E24
Mo
1E23
Fe
Zr
V
Si
Ti
Al
1E22
1E21
5
6
7
8
9
10
Ip,eV
Fig. RSFs as a function of Ionization potential of element.
Points show experimental RSFs, found by SIMS with
using of EDX data.
Fragments of mass- spectrum, acquired by SIMS for Ti allow
7
10
Al
6
10
O
Intensity,cps
5
10
Si
Na
4
10
C
3
10
++
O
2
10
Ti
O2
++
N
B
1
10
0
10
4
6
8 10 12 14 16 18 20 22 24 26 28 30 32 34 36
Z/q
Ti
7
10
V
6
10
TiO
Intensity, cps
5
Fe
Mn
K
Ca
10
4
TiO2
Cr
10
3
10
Ni
Se
2
10
1
10
0
10
30
40
50
60
Z/q
70
80
90
7
10
6
10
Ti2
Intensity, cps
5
10
Mo
Zr
Ti2O
4
10
MoO
In
3
TiMo
10
Cs
2
10
1
10
0
10
80
90
100
110
120
130
140
150
160
Z/q
7
10
6
10
Intensity, cps
5
10
4
10
3
10
2
10
1
10
0
10
170
180
190
200
Z/q
210
220
Table 1 Composition of Ti allow, defined by EDX/SIMS in
comparison with Certificate of the provider.
Elemento Certificate
EDX
SIMS
Falla, %
H
0.072%
n/d
0.091%
<26%
B
n/d
n/d
3E-4%
n/d
C
0.044%
n/d
0.050%
<15%
N
0.028%
n/d
0.062%
x2
Na
n/d
n/d
4E-4%
n/d
Al
2.72%
9.2%*
2.72%*
n/d
Si
0.12%
0.1%
0.1%
<15%
K
n/d
n/d
3E-6%
n/d
Ca
n/d
n/d
6E-5%
n/d
Ti
87.4%
83.2%*
87.4%
n/d
V
4.2%
4.5
4.5%
<7%
Cr
Suma: 0.03%
n/d
0.027%
n/d
n/d
0.011%
n/d
Mn
Fe
0.095
0.1
0.1%
<5%
Ni
Suma: 0.03%
n/d
0.002%
n/d
n/d
n/d
n/d
Cu
Zr
0.058
n/d
0.06%
<4%
Mo
2.7%
3.0%
3.0%
<10%
In
n/d
n/d
1.4E-4%
n/d
* Rose rows corresponds to elements used for SIMS calibration.
Conclusions:
1. EDX technique ideally complements SIMS for a
quantitative analysis of complex materials.
2. Any SIMS instrument, equipped by an Electron
Gun, can be “modified” to perform EDX analysis.
3. Energy of primary electron beam can be varied
from 0 to 10keV, this means we can vary thickness
of the analyzed layer from several microns down to
a hundred nanometers.
4. Standard-free analysis in the “full” range of
concentration: from 100 atomic % down to 10-7
atomic %, can be realized with a reasonable
accuracy.
THANK YOU FOR YOUR ATTENTION!