SiN depth profile using ion scattering
Using ion scattering, as typified by RBS, depth profile can be acquired for thin films with
various thickness, from ultrathin to thick films. High accurate composition including
hydrogen can be obtained . Here depth profile of ultrathin SiN film, and RBS / HFS / NRA
combination analysis of SiN film including carbon are presented below.
Ultrathin SiN film : HR-RBS / HR-HFS
Accurate depth profile, with approx. 1nm depth resolution, can be
provided by High resolution RBS / HFS (HR-RBS / HR-HFS).
Sample : SiN(8nm) / Si-sub.
1.0
100
1.5
HR-RBS
Observed
Simulated
3
1.0
Yield /10
0.5
N
H
0.5
O
0.0
320
Energy (keV)
360
Si
O
N
C
H
60
40
20
0
0.0
280
80
60
70
80
Energy (keV)
90
0
100
atomic%
Si
N
H
density
[g/cm3]
1.6～5.7
44.9
53.1
2.0
2.58
･ Depth resolution : approx. 1nm
･ Film density can be calculated
(film thickness needed)
For light elements below the detection limit of RBS, it is
useful to add NRA analysis. With the help of NRA,
precision and detection limit can be drastically improved.
Sample : SiN(94nm) / Si-sub.
1.0
3
3
Yield / 10
Yield / 10
3
Obs erved
Sim ulated
0.5
3.0
2.0
N
C
0.0
1000
Si
1.0
N O
C
100
NRA
4.0
2.0
500
5.0
HFS
Si
Yield /10
RBS
1500
2000
0.0
400
Energy (keV)
16
･ Composition without the effect
of surface / interface oxide
SiN including C : RBS / HFS / NRA
4.0
8
12
Depth (nm)
Depth profile
HR-RBS / HR-HFS spectra of ultrathin SiN film
region
[nm]
4
600
800
Energy (keV)
1000
Atomic Concentration(%)
Yield / 10
4
Si
Atomic Concentration (%)
HR-HFS
0.0
500
O
1500
2000
Si
N
H
C
density
[g/cm3]
1.7～92.3
38.6
44.4
13.2
3.8
2.31
40
20
0
50
100
150
Depth (nm)
200
Depth profile
RBS / HFS / NRA spectra of C including SiN
atomic%
Si
O
N
C
H
60
0
1000
Energy (keV)
region
[nm]
80
･ Accurate composition including
low concentration light elements
･ Detection limit of C
RBS : 5 at.%, NRA : 0.2 at.%
Toray Research Center, Inc.
P01108表面科学第２研究室20131111
STC：開(20141121)