skku. inorganic materials lab. highly ordered deposition of mgal-co 3 layered double hydroxides on...

Skku. Inorganic materials lab.Skku. Inorganic materials lab.

Highly Ordered Deposition ofHighly Ordered Deposition of MgAl-CO MgAl-CO33 Layer Layer

ed Double Hydroxides on Si(100) Surface by ed Double Hydroxides on Si(100) Surface by

SolvothermalSolvothermal TreatmentTreatment

이종현 , 이석우 , 송여진 , 정덕영 *

성균관대학교

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.



OH

OH

OH

OH

CO32-, nH2O

M(II), M(III)

M(II), M(III)

• General formula of synthetic LDH

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

• Schematic structure

Layered Double Hydroxide (LDH)

Micropatterning of LDH nanoparticles

Toluene Reflux(140C , 4hr)

Microcontact printing (OTS)

Coating (CP-TMS)

Ultra Sonication(30~60s)

Cl Cl Cl

o o o

CP-TMSglass

LDH

Si Si Si Si

Si Si Si Si Si Si Si

Si

o o o o o oo o o o

o o o o o o o o oo o o o o o

o o oSi Si

OH OH OH


Hydrothermal Treatment of LDH particles

Hydrothermal (140C ,

5hr)

A

B

A

B

AES(Auger Electron Spectrum)

OTS region (base resist) Etching

hydrothermal (180C ,

5hr)

AB Si(100)


Experimental section (solvothermal

treatment) 1. Wafer cleaning 2. Toluene solvothermal reaction (140C, 4hr)3. Ultra Sonication 5~10min4. Dry

Substrate N-type Si(100) :2E14 atoms/cm3 (dopant : phosphorus)

P-type Si(100) :1E15 atoms/cm3 (dopant : boron)

Toluene

LDH particles

Mg:Al=2:1

500nm

[Mg4Al2(OH)12]CO34H2O

Mg:Al=3:1

500nm

[Mg6Al2(OH)16]CO34H2

O

Mg:Al=4:1

500nm

[Mg8Al2(OH)20]CO34H

2O


10 20 30 40 50 60 70 80

0

5000

10000

15000

20000

(0015)

(0018)

Si(400)

(006)

(009)

(0012)

(003)

I(CPS)

2theta

Solvothermal Treatment

2m

500nm

p-type Si(100)

n-type Si(100)


2m

500nm

SEM image

X-RAY diffraction (film) [Mg4Al2(OH)12]CO34H2

O

X-RAY diffraction (powder & film)

(a) powder(b) film : substrate :n-type Si(100) (c) film : substrate :p-type Si(100)* : (00 l ) diffraction


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

Increase of surface coverage (SEM & AFM)

2m2m 1m

Mg:Al=2:1 Mg:Al=3:1 Mg:Al=4:1

Increase of Surface Coverage


AFM image

SEM image


A trend as temperature

AFM image

140C

150C 10 20 30 40 50 60 70 80

1300C

1500C

1400C

Si(400)

Si(200)

(0018)

(0012)(009)

(006)

(003)

intensity

2theta

X-RAY diffraction (film) [Mg4Al2(OH)12]CO34H2

O

Hydrothermal after solvothermal

[Mg4Al2(OH)12]CO34H2

O

수열

100C 5hr


2m

500nm

solvothermal

hydrothermal

2m

500nm

Increase of Surface Coverage

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( 140C ) 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.

AcknowledgementWe acknowledge support by the Korean Science and Engineering Foundation through Grant R02-2000-00065.

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