Highly Ordered Deposition of MgAl-CO3
Layered Double Hydroxides on Si(100)
Surface by Solvothermal Treatment
이종현 , 이석우 , 송여진 , 정덕영*
성균관대학교
Skku. Inorganic materials lab.
Abstract
Synthetic MgAl-CO3 layered double hydroxides(LDHs) are
inorganic layer-structured materials having homogeneous chemical
composition and sub-micron size. They crystallize in a hexagonal
systems with structural anisotropy. SEM and AFM images of the
film showed that LDHs particles were deposited on Si(100) with
high order by solvothermal treatment in toluene.
The surface coverage on Si(100) of LDHs particles increases as
the positive charge of layer decreases. The X-ray diffraction spectra
of the MgAl-CO3 LDHs deposited on Si(100) showed only the sharp
and intense (00l) reflections, suggesting that the LDHs layers are
parallel to the plane of Si(100). This work is an important evidence
for the direct chemical reaction between Si(100) surface and LDHs
particles.
Skku. Inorganic materials lab.
Layered Double Hydroxide (LDH)
• General formula of synthetic LDH
• Schematic structure
OH
M(II), M(III)
OH
CO32-, nH2O
OH
M(II), M(III)
M(II)1-xM(III)x(OH)2(Am-)x/mnH2O
M(II) = Mg, Ni, Zn
M(III) = Al, Cr, Fe
Am- = exchangeable anion.
0.2 ≤ x ≤ 0.4
1/m ≤ Am-/M(III) ≤ 1
OH
Skku. Inorganic materials lab.
Micropatterning of LDH nanoparticles
Microcontact printing (OTS)
Si
Si Si
o Si
o o o o OH OH OH o o o o o
glass
Coating (CP-TMS)
CP-TMS
Cl
Cl
Cl
Si Si Si
Si Si Si
o Si
o o oo o o oo o oo o oo
Toluene Reflux(140C , 4hr)
LDH
o
Ultra Sonication(30~60s)
Si
o
o
Si
o
o
Si
o
Skku. Inorganic materials lab.
Hydrothermal Treatment of LDH particles
AES(Auger Electron Spectrum)
Counts (E dN(E)/dE)
Hydrothermal (140C , 5hr)
B
A
4x10
3
3x10
3
2x10
3
1x10
3
A
0
-1x10
3
-2x10
3
-3x10
3
-4x10
3
Si
C
O
Si
Si
200
OTS region (base
resist)
600
800
1000 1200 1400 1600
Kinetic energy(eV)
1800
Etching
B
Si(100)
Counts (E dN(E)/dE)
1x10
A
400
#Pattern 1
As received
2000
2200
B
3
0
Si
C
-1x10
3
O
Si
Si
-2x10
3
200
hydrothermal
(180C , 5hr)
400
600
800
1000 1200 1400 1600
Kinetic energy(eV)
1800
2000
2200
Skku. Inorganic materials lab.
Experimental section (solvothermal treatment)
1. Wafer cleaning
2.
Toluene solvothermal reaction (140C,
4hr)
3. Ultra Sonication 5~10min
4. Dry
Toluene
LDH
particles
Substrate
N-type Si(100) :2E14 atoms/cm3 (dopant : phosphorus)
P-type Si(100) :1E15 atoms/cm3 (dopant : boron)
Mg:Al=2:1
Mg:Al=3:1
Mg:Al=4:1
[Mg4Al2(OH)12]CO34H2O
[Mg6Al2(OH)16]CO34H2O
[Mg8Al2(OH)20]CO34H2O
500nm
500nm
500nm
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Solvothermal Treatment
[Mg4Al2(OH)12]CO34H2O
SEM image
X-RAY diffraction (film)
(003)
20000
p-type Si(100)
S i(4 0 0 )
10000
(009)
(0015)
5000
(0018)
500nm
(0012)
I(CPS)
(006)
15000
0
2m
10
20
30
40
50
60
70
80
2theta
n-type Si(100)
(003)
150000
500nm
(006)
I(CPS)
100000
Si(200)
(009)
50000
2m
0
5
10
15
20
25
30
35
40
2theta
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X-RAY diffraction (powder & film)
(003)
(0018)
*
*
*
(b)
*
(a)
intensity
(0015)
*
*S i(200)
(009)
(006)
S i(400)
15000
*
(c)
10000
[M g 6 Al 2 (OH) 16 ]CO 3 -4H 2 O
*
(0012)
Intensity
20000
20000
Si(400)
(009)
*
(006)
[M g 4 Al 2 (OH) 12 ]CO 3 -4H 2 O
(003)
30000
*
(c)
10000
*
(b)
5000
*
*
0
(a)
0
10
20
30
40
50
60
70
80
10
20
2theta
*
60
70
80
S i(400)
S i(200)
6000
I(CPS)
50
d-value shift
(009)
*
(006)
8000
40
2theta
[Mg 8 Al 2 (OH) 20 ]CO 3 -4H 2 O
(003)
10000
30
(c)
*
4000
4:1
(b)
2000
3:1
(a)
2:1
0
10
20
(a) powder
(b) film : substrate :n-type Si(100)
(c) film : substrate :p-type Si(100)
* : (00 l ) diffraction
30
40
2theta
50
60
70
80
10
20
30
Mg:Al
(003)
(006)
(009)
2:1
7.66Å
3.81Å
2.54Å
3:1
7.82Å
3.91Å
2.61Å
4:1
7.92Å
3.96Å
2.64Å
40
2theta
Skku. Inorganic materials lab.
Increase of surface coverage (SEM & AFM)
SEM image Mg:Al=2:1
Mg:Al=3:1
2m
Mg:Al=4:1
2m
1m
Increase of Surface Coverage
AFM image
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A trend as temperature
[Mg4Al2(OH)12]CO34H2O
AFM image
(003)
X-RAY diffraction (film)
140C
(0018)
(0012)
S i(200)
(009)
intensity
(006)
S i(400)
0
140 C
0
150 C
0
130 C
10
20
30
40
50
60
70
80
150C
2theta
Skku. Inorganic materials lab.
Hydrothermal after solvothermal
[Mg4Al2(OH)12]CO34H2O
solvothermal
hydrothermal
수열
500nm
100C
5hr
2m
2m
(003)
Increase of Surface Coverage
200000
100000
(006)
50000
(009)
I(CPS)
150000
0
500nm
5
10
15
20
25
30
35
40
2theta
Skku. Inorganic materials lab.
Conclusion
We have seen that it was possible for MgAl-CO3 LDHs-nano size
particles to be deposited on Si(100) without intermediates and to
be micro-patterned on the CP-TMS region prepared by cp. LDHs
particles were deposited on Si(100) at unique temperature( 140C )
by solvothermal treatment in toluene.
SEM and AFM images of the film showed that LDHs particles
were deposited on Si(100) with high order by solvothermal
treatment in toluene. The surface coverage on Si(100) of LDHs
particles increases as the positive charge of layer decreases. This
work is an important evidence for the direct chemical reaction
between Si(100) surface and LDHs particles.
Acknowledgement
We acknowledge support by the Korean Science and Engineering
Foundation through Grant R02-2000-00065.
Skku. Inorganic materials lab.