Transcript Infrared Spectroscopy IR (FTIR) Leonid Murin 1,2 Joint Institute of Solid State and Semiconductor Physics, Minsk, Belarus Oslo University, Centre for Materials Science and Nanotechnology, Oslo,

Infrared Spectroscopy IR
(FTIR)
Leonid Murin 1,2
1
Joint Institute of Solid State and
Semiconductor Physics, Minsk, Belarus
2
Oslo University, Centre for Materials Science
and Nanotechnology, Oslo, Norway
OUTLINE
• Some general notes
• Electronic transitions
• Local Vibrational Mode spectroscopy
BACKGROUND - WHAT IS MEASURED
The light transmitted through a sample of thickness d with
polished parallel surfaces is described as
(1  R) 2 e d
I  I0
1  R 2 e  2 d
where:
I0 is the light intensity incident on the sample
α is the frequency dependent absorption coefficient
R is reflectivity (R ≈ [(n-1)/(n+1)]2 ≈ 0.3 in the mid infrared)
T = 300 K
(Bruker IFS 113v)
0.2
FZ-Si, d = 3 mm
Signal
0.1
0.0
-0.1
-0.2
400
600
800
1000
1200
1400
Wavenumber, cm
-1
1600
1800
2000
0.010
T = 300 K
(Bruker IFS 113v)
FZ-Si, d = 3 mm
Signal
0.005
0.000
-0.005
-0.010
800
1000
1200
1400
-1
Wavenumber, cm
1600
0.5
T = 300 K
(Bruker IFS 113v)
Background (without sample)
Signal
0.4
0.3
Raw spectrum, FZ-Si, d = 3 mm
0.2
Raw spectrum
Cz-3-J4, 24 GeV p-irr 1E16, d = 3 mm
0.1
0.0
400
600
800
1000
1200
1400
-1
Wavenumber, cm
1600
1800
2000
T = Raw spectrum of a sample / background
0.6
T = 300 K
(Bruker IFS 113v)
FZ-Si, d = 3 mm
Transmission
0.5
0.4
0.3
FZ-Si, d = 5 mm
0.2
0.1
0.0
400
600
800
1000
1200
1400
-1
Wavenumber, cm
1600
1800
2000
T = Raw spectrum of a sample / background
0.6
T = 300 K
(Bruker IFS 113v)
FZ-Si, d = 3 mm
Transmission
0.5
0.4
16
-2
CZ-Si, 24 GeV p-irr 1x10 cm , d = 3 mm
0.3
0.2
0.1
0.0
400
600
800
1000
1200
1400
-1
Wavenumber, cm
1600
1800
2000
A = -ln(I/I0)
4
T = 300 K
(Bruker IFS 113v)
Absorption
3
2
16
-2
CZ-Si, 24 GeV p-irr 1x10 cm , d = 3 mm
1
FZ-Si, d = 3 mm
0
400
600
800
1000
1200
1400
Wavenumber, cm
-1
1600
1800
2000
S = -ln(I/I0) - K x (-ln(Iref/I0))
1.2
T = 300 K
(Bruker IFS 113v)
1.0
16
-2
Absorption
CZ-Si, 24 GeV p-irr 1x10 cm , d = 3 mm
0.8
0.6
0.4
0.2
0.0
400
600
800
1000
1200
1400
-1
Wavenumber, cm
1600
1800
2000
S = -ln(I/I0) - K x (-ln(Iref/I0))
0.12
T = 300 K
(Bruker IFS 113v)
0.11
Absorption
0.10
0.09
0.08
16
-2
CZ-Si, 24 GeV p-irr 1x10 cm , d = 3 mm
0.07
0.06
800
850
900
950
Wavenumber, cm
1000
-1
1050
AC = S/d
4.0
T = 300 K
(Bruker IFS 113v)
18
Absorption coefficient, cm
-1
3.5
NO = 1.06x10 cm
-3
3.0
2.5
16
2.0
-2
CZ-Si, 24 GeV p-irr 1x10 cm , d = 3 mm
1.5
1.0
0.5
0.0
400
600
800
1000
1200
1400
Wavenumber, cm
-1
1600
1800
2000
AC = S/d
0.40
T = 300 K
(Bruker IFS 113v)
Absorption coefficient, cm-1
0.38
0.36
15
0.34
-3
NVO = 8.5x10 cm
I2 O
0.32
0.30
0.28
0.26
0.24
16
-2
CZ-Si, 24 GeV p-irr 1x10 cm , d = 3 mm
0.22
0.20
800
850
900
950
Wavenumber, cm
1000
-1
1050
DAC = S(irrad - as-grown)/d
0.45
T = 300 K
Absorption coefficient, cm-1
VO
0.40
I2O
0.35
IO2, I2O2
IO2, I2O2
0.30
O2i
16
O2i
-2
CZ-Si, 24 GeV p-irr 1x10 cm , d = 3 mm
0.25
Oi
0.20
800
850
900
950
1000
Wavenumber, cm
1050
-1
1100
1150
Low temperarure measurements
0.8
VO
16
-3
16
-2
+
1 - Cz1-I4 ([CS = 5x10 cm ) RT irr 1x10 cm p 26 GeV
15
-3
16
-2 +
2 - Cz3-J4 ([CS < 1x10 cm ) RT irr 1x10 cm p 26 GeV
CiOi
15
-3
16
-2
+
3 - Cz3-J3 ([CS < 1x10 cm ) DAC: RT irr 1x10 cm p 26 GeV - hot irr
0.6
ICiOi
Absorption coefficient, cm
-1
18
VO
Oi
ICi
-
1
0.4
I2O
2
IO2
0.2
I2O2
I2O2
IO2
3
0.0
V2O2
O2i
O2i
-0.2
T = 20 K
VO2
800
850
900
950
Wavenumber, cm
1000
-1
1050
1100
V2 generation
1.0
16
T = 20 K
-2
+
RT irr 1x10 cm p 24 GeV
15
4.7x10 cm
1 - Fz1-I3 (O,C-lean, as-grown)
2 - Cz3-J4 (C-lean, as-grown)
3 - Cz3-J3 (C-lean, hot irr)
4 - Cz1-I4 (C-reach, as-grown)
Absorption coefficient, cm
-1
0.8
4
-3
15
3.3x10 cm
0.6
0.4
15
2x10 cm
3
-3
2
-3
1
15
1.5x10 cm
0.2
-3
0.0
2700
2720
2740
2760
2780
Wavenumber, cm
-1
2800
2820
2840
Electronic transitions
• Shallow donors and acceptors
• Group VI (S, Se, Te) etc
• Thermal double donors (as an example:
L.I. Murin, V.P. Markevich, J.L. Lindstrom, M. Kleverman
Spectroscopic observation of the TDD0 in silicon,
Physica B 340–342 (2003) 1046–1050).
TDD0 observation
p-type Cz-Si
( = 80 Ohmcm)
18
0.15
TDD1(2p±)
-3
[Oi] = 1.1x10 cm
1 - 1250 C 40 min H2 gas
2 - 300 C 2 h
3 - difference 2-1
-1
Absorption coefficient, cm
T = 15 K
1
0.10
2
0.05
TDD0(2p±)
O2i
TDD1
O3i
O2i
TDD1 (2p0)
TDD0 (2p0)
TDD0
O2i*
O3i
3
0.00
OiH2
900
1000
1100
-1
Wavenumber, cm
1200
1300
TDD0 observation
0.06
TDD1(3p±)
Fragment of the difference spectrum
300 C 2 h (air) - 1250 C 40 min (H2)
Absorption coefficient, cm
-1
0.05
0.04
0.03
TDD0(3p±)
TDD1(4p±)
0.02
TDD1(5p±)
0.01
TDD1(6p±)
TDD0(4p±)
TDD0(5p±)
TDD1(4f±)
TDD0(4f±)
TDD0(6p±)?
0.00
1160
1180
1200
1220
1240
Wavenumber, cm
-1
1260
1280
1300
Detection limit
Calibration:
α = 1 cm-1 corresponds approximately
to NTDD = 1013 cm-3
Detection of α = 0.01 cm-1 (NTDD = 1011 cm-3) is
reliable
LVM spectroscopy
“LVM spectroscopy assumes now a very central role
among
the
large
number
of
semiconductor
characterization techniques which have been developed
over the years and which are continuously refined and
improved. When applicable, this technique allows, in
many cases, the precise identification of impurity species
and their crystal lattice location with excellent sensitivity.
Besides, LVM spectroscopy with perturbations such as
polarization of the probe light, uniaxial and hydrostatic
stress, and isotope substitution can be highly successful
in identifying the structure and composition of various
kinds of defect complexes.”
E.E Haller, Mat. Res. Soc. Symp. Proc. Vol. 378 (1995) 547-565.
Detection limits
Depend on:
Measurement temperature (LT or RT)
Sharpness of the lines
Wavenumber position
Detection limits normally are in the range
5x1013 – 1x1015 cm-3)
16
T = 20 K
0.20
Fz1-I2
15
1 - as-grown, [Oi] = 2x10 cm
-
-3
18
-2
15
2 - e 6MeV 330-340 C 1x10 cm , [Oi] = 1.5x10 cm
-3
Absorption coefficient, cm
-1
0.15
3 - difference between 2 and 1
0.10
N2
1
?
N2
0.05
2
3
0.00
VO, V2O
-0.05
800
900
1000
Wavenumber, cm
-1
1100
Oi
0.04
T = 20 K
Fz1-I3
16
-2
+
Difference: RT irr 1x10 cm p 24 GeV - as-grown
0.02
Absorption coefficient, cm
-1
VO
14
V2O
NVO + NV2O = 5x10 cm
-3
0.00
N2
-0.02
Oi
-0.04
800
850
900
950
1000
1050
Wavenumber, cm
-1
1100
1150
1200
0.20
T = 20 K
Fz1-I3
0.15
15
-1
Absorption coefficient, cm
-3
As-grown, NO of about 2x10 cm
0.10
0.05
N2
N2
0.00
Oi
750
800
850
900
950
1000
Wavenumber, cm
-1
1050
1100
1150
1200