IIT JAM Chemistry 2022 Question Paper | Sourav Sir's Classes
Oral presenation AVS 2013 Liwang 10-25-13
1. Surface Reactions During ALD of
TiO2 on GaAs Surfaces Studied by
in situ ATR-FTIR
Liwang Ye, Theodosia Gougousi
Department of Physics, University of Maryland, Baltimore County,
Baltimore, MD 21250
1
University of Maryland, Baltimore County
2. 2
University of Maryland, Baltimore County
Motivation
ALD of high k on III-V has
promising applications on
MOSFET.
Poor native oxides are the
main difficulties for the
applications.
Interface self-cleaning has
been widely discovered.1
1. P. D. Ye et al. APL 83, 180 (2003), M. M. Frank et al. APL 86, 152904 (2005), D. Shahrjerdi et al. APL 92, 223501
(2008), L. Huang et al. APL 87, 252104 (2005), C.-H. Chang et al. APL 89, 242911 (2006),C. L. Hinkle et al. APL 92,
071901 (2008), Hackley et al. APL 92(16), 162902 (2008) , Suri et al. APL 96, 112905 (2010).
Gougousi et al. TSF 518, 2006 (2010)
Gougousi et al. JES, 157(5), H551 (2010)
3. 3
Si
TiO2
Ti
N(CH3)C2H5(CH3)C2H5N
(CH3)C2H5N N(CH3)C2H5
TEMAT
B. Kan et al., J. Phys. Chem. A
113(16), 3946 (2009).
M. Bouman et al., ECS
Transactions, 33 (2) 291-305
(2010).
Si
HfO2
TDMAH Hf
N(CH3)(CH3)N
(CH3)N N(CH3)
K. Li et al., J. Phys. Chem. C
114, 14061 (2010).
Y. Wang et al., and T.
Gustafsson, Chem. Mater.
2007, 19, 3127-3138 3127.
K. Li et al., J. Phys. Chem. C
2011, 115, 18560–18571.
Hf
N(CH3)C2H5(CH3)C2H5N
(CH3)C2H5N N(CH3)C2H5
Hf
N(C2H5)2(C2H5)2N
(C2H5)2N N(C2H5)2
TEMAH
TDEAH
M. J. Kelly et al., Chem. Mater.
2005, 17, 5305-5314.
In situ FTIR study of high k ALD on Si
University of Maryland, Baltimore County
4. 4
To detector IR incidenceIRE (GaAs)
IR
detector
IR
source
Pump
H2O TDMAT
FTIR ATR cell
Pressure
gauge
N2
K. Li, S. Li, N. Li, D. A. Dixon, and T. M. Klein, J. Phys. Chem. C 114, 14061 (2010).
Experiment details: in situ ATR-FTIR setup
University of Maryland, Baltimore County
~12 total reflections
on top surface
5. • Precursor: TDMAT and H2O
5
1stTDMAT
1stH2O
Time (min)0 3 4 5 6 7
Pumpand
takespectra
Pumpand
takespectra
1st Cycle
2nd Cycle
Reactor
pressure
Note: Y-axis only serves as a guide for
understanding the procedure.
Ti
N(CH3)2(CH3)2N
(CH3)2N N(CH3)2
TDMAT
Experimental details: ALD process
University of Maryland, Baltimore County
6. 6
GaAs surface preparation
University of Maryland, Baltimore County
Absorbance
4000 3000 2000 1000
Wavenumber (cm
-1
)
CO GaAs
F GaAs
H2O
C-H
H2O
As-O
As-O
As-O or
Ga-O
free
OH
“F GaAs” surface:
etched in BOE
“CO GaAs” surface:
“F GaAs” soaked in
(30%)H2O2 at 45°C
for 10~30mins.
GaAs
chemical oxide
TiO2
~3nm
Reference: native oxide GaAs
Reference:
F GaAs
M. Rei Vilar et al. Surf. Interface Anal. 37, 673 (2005).
7. Absorbance
4000 3500 3000 2500 2000 1500 1000
Wavenumber (cm
-1
)
TiO2 / CO GaAs 100C
1
st
TDMAT
1
st
H2O
2
nd
TDMAT
2
nd
H2O
20
th
TDMAT
20
th
H2O
1598
1466
1409
0.004
7
CH3 stretching
from TDMAT
ALD of TiO2/CO GaAs(100) at 100°C
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NC2 stretching
from TDMAT
TiO2
9. Possible assignments of the 1598 cm-1:
H-O-H bending mode of H2O.
OCO stretching of formate (HCOO) .
OCO stretching of carbonate (HCO3).
N-H bending mode of methylamine (CH3NH2).
C=N stretching of Methylmethyleneimine
(CH3N=CH2) (MMI).
9
Discussion: the possible assignments
University of Maryland, Baltimore County
10. D2O H2
18O
D2O
Or H2
18O
Species Liquid H2O
MMA
CH3NH2 on
TiO2
Formate
HCOO
Bidentate
carbonate
HOCOOTi
MMI
(CH3N=CH2)
Modes Scissoring
NH2
scissoring
Anti. Sym.
OCO
stretching
OCO Sym.
stretching
N=C
stretching
Peak (cm-1) ~1620 1607 1607 1582 ~1590
Peak with
isotope
D2O CH3ND2 HC18O18O H18OC18O18O CH3N=CH2
~1200 1205 1587 1570 ~1590
Shift (cm-1) 400 ~400 20 ~12 0
References
R. Nakamura, et al.
Langmuir 17,
2298(2001)
Li. –F. Liao et al. J.
Phys. Chem. B 105,
5928(2001).
L.-F. Liao et al., J.
Phys. Chem. B,
106(43), 11241
(2002).
L.-F. Liao et al., J.
Phys. Chem. B,
106(43), 11241
(2002).
C. M. Truong et al.
J. Phys. Chem. 99,
8831(1995).
10
Isotope exchange experiments
University of Maryland, Baltimore County
11. Absorbance
4000 3500 3000 2500 2000 1500 1000
Wavenumber (cm
-1
)
1598
1466
1409
10 cyc of TiO2 on CO GaAs 100C
ALD with H2
16
O
ALD with H2
18
O
0.001
• D2O exchange excludes the assignments of H2O and CH3NH2.
• H2
18O exchange experiment excludes the possibilities of
formate and carbonate species.
11
Absorbance
4000 3500 3000 2500 2000 1500 1000
Wavenumber (cm
-1
)
1598
1466
1409
10 cyc of TiO2 on CO GaAs 100C
2400
ALD with D2
16
O
ALD with H2
16
O
0.001
Isotope exchange experiments
University of Maryland, Baltimore County
12. 12
O
H
HO O
Ti
N(CH3)2
N(CH3)2
+ N=CH2CH3-
+ O O
Ti
O-H
O-H
HN(CH3)2
O O
Ti
N(CH3)2
N(CH3)2
-N(CH3)2 + H
N=CH2CH3- + H2
O O
Ti
O-H
O-H
+
O O
Ti
N(CH3)2
N(CH3)2
+
HN(CH3)2
Mechanism ?
2 -N(CH3)2+
N=CH2CH3-
+
Ref. 2
1. J. P. A. M. Driessen et al., J. Electrochem. Society, 148(3), G178(2001).
2. S. Salim et al., Chem. Mater. 7, 507(1995).
((CH3)2N)xE + H ((CH3)2N)x-1E + H2 + H2C=NCH3 E: As, P, Sb; x=1,2,3
Ref. 1+H2 2 + H2
Reaction scheme
University of Maryland, Baltimore County
O
H
H
O
H
H
13. 13
O
H
HO O
Ti
N(CH3)2
N(CH3)2
+ N=CH2CH3-
+
O O
Ti
O-H
O-H HN(CH3)2
O O
Ti
N(CH3)2
N(CH3)2
-N(CH3)2 + H
N=CH2CH3- + H2
O O
Ti
O-H
O-H
+
O O
Ti
N(CH3)2
N(CH3)2
+
HN(CH3)2
Mechanism ?
2 -N(CH3)2+ N=CH2CH3-+
Ref. 2
1. J. P. A. M. Driessen et al., J. Electrochem. Society, 148(3), G178(2001).
2. S. Salim et al., Chem. Mater. 7, 507(1995).
((CH3)2N)xE + H ((CH3)2N)x-1E + H2 + H2C=NCH3 E: As, P, Sb; x=1,2,3
Ref. 1
+H2 2 + H2
Reaction scheme for revison
University of Maryland, Baltimore County
O
H
H
O
H
H
14. 14
Effect of ALD temperature and surface
preparation
University of Maryland, Baltimore County
Absorbance
4000 3500 3000 2500 2000 1500 1000
Wavenumber (cm
-1
)
20 cyc of TiO2 on GaAs
CO GaAs 100 C
CO GaAs 200 C
1598
1466
1409
0.002
F GaAs100 C
F GaAs 200 C
15. Absorbance
4000 3500 3000 2500 2000 1500 1000
Wavenumber (cm
-1
)
1
st
TDMAH
2
nd
TDMAH
30
th
TDMAH
1
st
H2O
2
nd
H2O
30
th
H2O
ALD HfO2/CO GaAs at 275C
Reference: CO GaAs
1598
1466
1409
0.004
• The spectrum of 30 cycles of HfO2 resembles the one from ALD of
TiO2 on GaAs. A broad negative peak is growing at As-O region.
15
ALD HfO2/CO GaAs
University of Maryland, Baltimore County
Absorbance
1200 1100 1000 900 800
Wavenumber (cm
-1
)
0.004
As-O region
16. 16
As oxide removal was observed during the deposition at 275°C
but was not observed at 200°C.
GaAs oxide removal
University of Maryland, Baltimore County
Absorbance
1400 1300 1200 1100 1000 900 800
Wavenumber (cm
-1
)
As-O
B: As-prepared
CO GaAs (RT)
A: After 30cyc HfO2
cooled down to RT
As-O
A-B: Difference of two spectra
0.01
ALD HfO2/CO GaAs at 275C
Reference:
etched GaAs surface
17. For the deposition of TiO2 on GaAs surface,
Methylmethyleneimine (MMI) was produced
during the H2O exposure and accumulates in
the film.
As oxide removal was observed during the
deposition on HfO2 on chemical oxide GaAs
surface at 275°C but was insignificant at
200°C.
17
Conclusions
University of Maryland, Baltimore County
Keep the title as abstract
Talk about the TiO2 peaks issue first.
Use a template. Make it uniform.
Rephrase the self-cleaning amime precuors.
Reference just for self-cleaning.
Just use the 1st author.
There is very little publication about using in situ FTIR to study the surface reactions and native oxide during the ALD of high k on III-V surface.
Front size need to be larger. Make the image bigger.
Larger TDMAT molecule or remove it.
Make lines bigger.
Larger TDMAT molecule or remove it.
Speak: to emphasize the point of the spectra.
Axis label too small.
Shift up the spectra to make them bigger. Make image bigger.
Some CH peaks and peaks at 1600, 1466 and 1409 cm-1 accumulate during the deposition.
: CH not “on the surface.”
“Decrease” is not in order.
Remove the first set of animation before the second. Title of plot needs to be bigger.
Subscript and superscript “TiO2”. Bullet need to be consistent. Molecule drawing?
Motivation: by applying D2O and H2O (18O), we should be able to tell if these species are H2O, MMA, formate or carbonate based on their shift of the peaks.
Adjust the middle column width. Superscript and subscript. Capitallize the title.
The font size on the plot.
Super and subcript. “Methylamine”
Title. Font size. Show the reacitons one by one. “think about the production of As-N(CH3)2
Title. Font size. Show the reacitons one by one. “think about the production of As-N(CH3)2
Line thickness to small. Make it 2.
Rephrase or talk about it a little more.
Native oxide to the etched surface spectra. Font size.
Mentioned no more oxide removal at 200C.
Make line thicker. Put a box ~850cm-1.
Two subscrpt for HfO2.
Line thiciker. Degree simbol.
