Transcript Slide 1

Thermodynamics and Kinetics study
of growth behavior of sono-electrodeposited Cu thin films
Sabita Rout, A. Mallik, B. C. Ray
[email protected]
[email protected]
[email protected]
,
Department of Metallurgical and Materials Engineering
National Institute of Technology, Rourkela

Growth of thin films – an insight

The growth parable

Sono-electrodeposition technique

Experimental /Results and discussion

Conclusions

References
Growth of thin films
(Time bound Grain growth)
(Property change with variation of grain size)
Harper et.al, Journal of applied Physics, 86 (1999) 2516-2524
The growth Parable
Grain growth mechanism
Sources
 Grain boundaries
 Stacking faults
 Dislocations
 Surface energy
 Elastic strain
 Pinning particles
 Ostwald ripening
Triple junctions
 Zener pinning
Two modes of grain growth
 Normal grain growth
 Abnormal grain growth
Model 2
Model 1
Sequence of
different sizes
Different sizes
Model 4
Model 3
Sequence of
same sizes
Same sizes
(Growth models)
Normal vs. abnormal grain growth
Normal grain growth
Follows a parabolic law
D  D02  Kt
Abnormal grain growth
Grain boundary velocity is given by
v  ( CG / TV ) exp( G
m
a
/ RT )
Diameter of grains comparable to the
film thickness
Diameter of grains exceeds ten times
the film thickness
 Growth is slow and steady
 Growth is rapid and abrupt
A monomodal distribution of grain sizes A bimodal distribution of grain sizes
after growth
after growth
Sono-electrodeposition
The coupled effect of electrochemistry and ultrasound
• Extreme fast mass transport
• Affects the crystallization process
• Degassing at the electrode surface
(The effects)
(A cavitation
bubble)
cavitation
(The
equipment)
Reaction kinetics - > cyclic voltammetry
0.14
b
0.12
0.10
Current (A)
0.08
a
0.06
0.04
0.02
0.00
-0.02
5C
10 C
15 C
20 C
25 C
-0.04
-0.06
-0.08
-0.10
-0.12
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
Potential (V)
Cyclic Voltammetry of copper deposits at (a)Sonicntion (b) Silent
Bath temp (°C)
Oxidation
potential (V)
Cathodic
efficiency
5
+0.567
1.6
10
+0.626
0.79
15
+0.626
0.92
20
+0.626
0.72
25
+0.626
0.84
Portela et.al , Electrochimica Acta, 51 (2006) 3261-3268
Nucleation mechanism - > Chrono amperometry analysis:
-0.015
Current/A
-0.020
-0.025
5C
10 C
15 C
20 C
25 C
-0.030
-0.035
0
5
10
15
20
Time/sec
(Deposition at silent condition)
(Deposition at -0.3V)
Table: Characteristic kinetic parameters of current transients obtained for sonicated copper deposits
2
Bath temp
20 °C Imax (A/cm )
(°C)
tmax(s)
D x 10-9
(cm2 s-1 )
N x 1010
(cm-2 )
5
0.0228
1.726
1.1673
4.5604
10
0.0184
0.885
1.2246
3.273
15
0.0175
1.139
1.4257
2.1844
20
0.0162
1.349
1.447
1.8171
25
0.0238
1.685
3.9011
0.5396
Mallik et.al , Electrochemical and Solid State Letters, 12 (2009) F46-F49
Han et.al, Electrochimica Acta, 54 (2009) 3419-3427
Thermodynamics and Kinetics - > DSC analysis:
 Heat release increases with decrease
in temperature
 The exothermic peak observed around
320°C
 Activation energy is in the range,
0.85-2.9 eV
(DSC thermograms at scan rate of
5°/min )
Kissinger equation
-9.8
-10.0
-10.2
Ln(/Tm2)
-10.4
Table: Activation energies
-10.6
-10.8
-11.0
-11.2
5C
10C
15C
20C
25C
-11.4
0.00150
0.00151
0.00152
0.00153
0.00154
0.00155
0.00156
0.00157
0.00158
0.00159
0.00160
0.00161
0.00162
0.00163
Copper deposition at (°C)
Activation energy
(eV/atom)
5
0.85
10
2.90
15
1.51
20
1.50
25
1.35
1/Tm(1/K)
Growth mode - >surface energy
(Water on deposit )
Table: Surface energy values
Temperature
(°C)
S. E (mN/m)
Before DSC
S.E (mN/m)
After DSC
5
59.92
55.62
10
51.58
34.24
15
45.84
67.86
20
41.77
43.21
25
30.48
32.30
(SE determination by
Owens-Wendt & Kaelble
(OW) method)
 Decrease in temperature – increase in
SE
 Fluctuations in SE after thermal
treatment – abnormal to normal growth
behavior
XRD analysis
40
50
60
Cu(111)
450
a
15 C
20 C
25 C
b
400
C(1011)
Cu(022)
Cl(721)
Cu(113) 25 C
20 C
Intensity(arb.units)
Intensity(arb.units)
500
1600
1500
1400 Cu(111)
1300
1200
1100
S(0214)
Cu(200)
1000 S(062)
900
800
700
600
500
400
300
200
100
0
350
300
Cu(200)
S(062)
S(0214)
90
Cl(721) Cu(113)
200
150
100
10 C
50
0
40
80
Cu(022)
250
15 C
5C
70
C(1011)
50
60
70
80
90
100
2(degree)
100
2(degree)
XRD plots of copper deposits (a) before DSC (b) after DSC
A
Bath
temperature
(°C)
Size (nm)
Strain x 10-3
5
12.4416
5.5025
10
22.3809
15
B
Bath
temperature
(°C)
Size (nm)
Strain x 10-3
4.0702
15
102.119
1.81075
53.159
2.1285
20
116.4013
1.0675
20
65.5048
1.815
25
182.5815
0.2787
25
230.5810
0.0475
Size and strain calculated from XRD plots for copper thin film (A) before DSC (B) after DSC
SEM analysis both before and after DSC:
a
a
b
c
d
e
f
g
h
i
jj
c
d
Model-1
Model-4
Model-1
(SEM images of copper deposited at 5 °C, 10°C, 15°C, 20°C, 25°C under
sonication condition (a-e) as deposited (f-j) after DSC)
Conclusions
 Better adherence of deposit by sono-electrodeposition.
 The appearance of exothermic peak signifies occurrence of grain growth.
 Determination of activation energy provides information about the
kinetics of grain growth.
 Whether proposed growth mechanism are the correct way to explore
grain growth, will remain unclear until further investigations down to
single grain or monolayer films
References
1. J. M. Zhang, K. W. Xu, V. Ji. Competition between surface and strain energy during grain growth in free-standing and
attached Ag and Cu films on Si substrates. Applied surface science 187 (2002) 60-67.
2. J. M. E. Harper, C. Cabral, P. C. Andricacos, L. Gignac, I. C. Noyan. Mechanisms for microstructure evolution in
electroplated copper thin films near room temperature. Journal of applied physics 86 (1999) 2516-2525.
3. F. P. Luce, P. F. P. Fichtner, L. F. Schelp. Abnormal grain growth behavior in nanostructured Al thin films on SiO2/Si
substrate. Material Research Society 1150 (2009) RR03-06.
4. C. Detavernier, S.Rossnagel, C. Noyan, S. Cabral. Thermodynamics and kinetics of room-temperature microstructural
evolution in copper films. Journal of applied physics 94 (2003) 2874-2881.
5. A. Mallik, A. Bankoti, B. C. Ray. A Study on the Modification of Conventional Electrochemical Crystallization under
Sonication: The Phenomena of Secondary Nucleation. Electrochemical and Solid-State Letters 12 (2009) F-46-F-49.
6. R. Cow, R. Blindt, R. Chivers, M. Povey. A study on the primary and secondary nucleation of ice by power ultrasound.
Ultrasonics 43 (2005) 227-230.
7. D. Bera, S. C. Kuiry, S. Seal. Kinetics and Growth Mechanism of Electrodeposited Palladium Nanocrystallites. Journal of
Physical Chemistry 108 (2004) 556-562.
8. R. Finsy. On the Critical Radius in Ostwald Ripening. Langmuir 20 (2004) 2975-2976.
9. K. B. Yin, Y.D. Xia, C. Y. Chan, W. Q. Zhang. The kinetics and mechanism of room-temperature microstructural evolution
in electroplated copper foils. Scripta Materialia 58 (2008) 65-68.
10. S. Villain, P. Knauth, G. Schwitzgebel. Electrodeposition of Nanocrystalline Silver: Study of Grain Growth by
Measurement of Reversible Electromotive Force. Journal of Physical Chemistry 101 (1997) 7452-7454.
11. H. E. Kissinger. Reaction Kinetics in Differential Thermal Analysis. Analytical Chemistry 29 (1957) 1702-1706.
12. L. Zhou, H. Zhang, D. J. Srolovitz. A size effect in grain boundary migration: A molecular dynamics study of bicrystal
thin films. Acta Materialia 53 (2005) 5273-5279.
13. S. K. Donthu, M. Vora, S. K. Lahiri, C. V. Thompson. Activation Energy Determination for Recrystallization in
Electroplated-copper films using Differential Scanning Calorimetry. Journal of Electronic Materials 32 (2003) 531-534.
14. P. Knauth, A. Charai, P. Gas. Grain growth of pure nickel and of Ni-Si solid solution studied by Differential Scanning
Calorimetry of nanometer-sized crystals. Scripta Metallurgica Materialia 28 (1993) 325-330.