Materials Sciences and Applications, 2010, 1, 187-190
doi:10.4236/msa.2010.14029 Published Online October 2010 (http://www.SciRP.org/journal/msa)
187
Synthesis and Electrical Characterization of
BaTiO3 Thin Films on Si(100)
Vijay Ramkrishna Chinchamalatpure, Sharada Arvinda Ghosh, Gajanan Niranjanrao Chaudhari
Nanotechnology Research Laboratory, Shri Shivaji Science College, Amravati, India.
Received May 10th, 2010; revised June 13th, 2010; accepted July 29th, 2010.
ABSTRACT
BaTiO3 thin film has been deposited on Si(100) substrate using sol-gel process and deposited by using spin – coating
technique. The BaTiO3/Si(100) structures were studied by structural and electrical characteristics. The X-ray diffrac-
tion of BaTiO3/Si(100) shows that the diffraction peaks become increasing sharp with increasing calcination tempera-
tures indicating the enhance crystallinity of the films. Scanning electron microscopy of BaTiO3 thin films shows the
crack free and uniform nature. The capacitance-voltage measurement of BaTiO3 thin film deposited on Si(100) an-
nealed at 600 ℃ shows large frequency dispersion in the accumulation region. The current-voltage measurement of
BaTiO3/Si shows the ideality factor was approaches to unity at 600 ℃ .
Keywords: Sol-Gel Technique, BaTiO3 Thin Film, C-V, I-V
1. Introduction
Barium Titanate (BaTiO3), a well-known dielectric mate-
rial has been used as an insulating material to fabricate
MIS structures. BaTiO3 exhibits several advantages,
properties such as high charge storage capacity, good
insulating property, low leakage current density and high
dielectric breakdown strength. It is also a potential mate-
rial for active microwave tunable device because of its
variable dielectric constant under external electric field.
It has also been shown that BaTiO3 works as an excellent
buffer layer for YBa2Cu3O7-δ high-Tc superconductor on
various substrates, in particular Si and Al2O3 [1]. Re-
cently, J. S. Lee et al. [2] fabricated n-MOSFET struc-
tures sequentially with the CMOS process and investi-
gated the insulator characteristics, programming and re-
sistance behaviour of BaTiO3 films. BaTiO3 are trans-
parent in the visible and infrared [3] and possess strong
electro-optic coefficients making them attractive for ac-
tive and passive optical components.
BaTiO3 thin film can be grown using pulsed laser de-
position [4], chemical vapor deposition (CVD) [5], metal
organic chemical vapour deposition [6-7], polymeric
precursor method [8-11], sol-gel synthesis [12] and mo-
lecular beam epitaxy (MBE) [1,13]. MBE can be used to
grow complex oxide thin film substrate with atomic layer
accuracy [14]. High quality BaTiO3 thin films are gener-
ally grown on lattice matched substrate such as MgO and
SrTiO3. Integration of BaTiO3 thin film with silicon
processing may enable the properties of ferroelectric to
be utilized in combination with CMOS in multi material
integration. Ion beam – assisted deposition of various
template layers such as MgO and Yttria – stabilized zir-
conia has been used to develope thin film of super con-
ducting YBa2Cu3O7 as well as oriented layers of (Pb, Ba)
TiO3 [15,16].
In recent years, the sol-gel technique has gained inter-
est in the area of processing of thin films because of the
several advantages it offers, such as easier composition
control, better homogeneity, low processing temperature
and low equipment cost [17]. For the present investiga-
tions BaTiO3 thin films have been deposited on Si(100)
substrates using sol-gel technique through organic pre-
cursor route.
2. Experimental Details
(100) oriented Si wafers were well rinsed with warm
acetone and methanol followed by etching in HNO3/HF
(1:1) for 1 minute. BaTiO3 thin films were deposited on
the polish side of the Si using sol-gel process.
Barium acetate (Sigma Aldrich, UK) and Titanium
butoxide were used as a starting material. Barium acetate
was dissolved in glacial acetate acid and reflux in a re-
flex condenser at a temperature of about 120℃ for six

Synthesis and Electrical Characterization of BaTiO3 Thin Films on Si(100) 188
hours to obtain a clear solution, after obtaining a clear
solution, Titanium butoxide was added in a proper mole
ratio and the solution was stirred to get homogenous
precursor. The viscosity of the solution was varied by the
addition of 2-methoxy ethanol. The precursor solution
was coated on Si(100) wafers by spin coating technique.
The spin coating was done at the rate of 3000 rpm. The
film was annealed at 300℃ and 600℃ for 30 minutes.
The focus of the present work is to study of BaTiO3
thin films prepared by the sol gel technique and depos-
ited by using spin – coating technique. The BaTiO3/
Si(100) structures were studied by structural and electri-
cal characteristics. The crystalline nature and the phase
formation of the deposited thin film were confirmed by
power X-ray diffraction analysis using Cukα radiation (α
= 1.5418 A.U.) surface morphology of the film were ob-
served using scanning electron microscopy.
The C-V characteristics of the MIS diodes were meas-
ured at 1 MHz frequency at room temperature in the dark
using a lock in amplifier (EG & G Model 5204). The
ohmic contact was made on the back side of Si(100) by
successive deposition of Au-Ge (2:1) alloy under a vac-
uum of 10-6 mbar and annealed at 400℃ under argon
atmosphere for 2 minutes.
3. Results and Discussion
The crystalline quality of BaTiO3 precursor were pre-
pared by sol-gel technique and deposited by using spin –
coating technique. The Figure 1 shows the XRD pattern
of BaTiO3 thin film on Si(100) substrate with different
annealing temperatures. As deposited BaTiO3 thin film
and annealed at 300℃ shows amorphous in nature. The
crystalline behaviors of the deposited BaTiO3 thin film
annealed at 600℃ shows sharp peaks indicating the en-
hance the crystallinity of the films. The structure of the
BaTiO3 thin film was found to be tetragonal.
Figure 2 show the FTIR spectra of BaTiO3 thin films
annealed at 600℃. The intense band at the edge of detec-
tion (260 cm-1) is assigned to Ti-O mode in developed
network [13]. The Figure shows that the broad and strong
band observed at 450 cm-1, characteristics of Ti-O bond.
Figure 3 (C1 & C2) shows the SEM micrograph of
BaTiO3 thin films annealed at 300℃ and 600℃. The
BaTiO3 thin films deposited on Si(100) annealed at 300℃
shows the agglomeration of the films shown in Figure 3
(C1). The BaTiO3 thin films deposited on Si(100) an-
nealed at 600℃ shows the films became crack free and
uniform nature.
The electrical properties of BaTiO3/Si(100) were stud-
ied by using 1 MHz capacitance-voltage characteristics.
Figures 4(a) and (b) shows room temperature C-V char-
acteristics for the sample annealed at 300℃ and 600℃ of
BaTiO3/Si(100). Figure 4(a) shows that the capacitance
Figure 1. XRD pattern of BaTiO3 thin film on Si(100) sub-
strate annealed at 600℃.
Figure 2. FTIR spectra of BaTiO3 thin films annealed at
600℃.
remains unchanged with in that bias range. Figure 4(b)
shows BaTiO3 thin film deposited on Si(100) and an-
nealed at 600℃ showed large frequency dispersion in the
accumulation region. The capacitance was changed from
the inversion value to a value above flat band capacitance
at 1 MHz. The electrical properties of BaTiO3/Si(100)
structure improved with annealing temp. at 600℃ shown
in Figure 4(b). The result shows that the deposited Ba-
TiO3 insulator is good enough to use as gate insulator of
MIS FET.
For 300℃ annealed temperature, the C-V curve shows
virtually flat which is an evidence of little modulation of
the surface potential by the applied voltage, However
when the film is subjected at 600℃ annealing tempera-
ture the C-V plot shows a dramatic change in the 1 MHz
freq. C-V behavior and considerable reduction in the
frequency dispersion suggest a much closer approach to

Synthesis and Electrical Characterization of BaTiO3 Thin Films on Si(100) 189
Figure 3. SEM of BaTiO3 thin films annealed at (C1) 300℃
and (C2) 600℃.
Figure 4. Capacitance-voltage characteristics of BaTiO3/Si
(100) annealed at (a) 300℃; (b) 600℃.
surface accumulation, i.e., usually observed in the metal
insulator semiconductor structure. Hence, the electrical
properties of BaTiO3/Si(100) MIS structure improved
with annealing temperature at 600℃.
Figure 5 shows Current-Voltage (I-V) Characteristics
of a typical diode with 90 Ao thick BaTiO3 film on Si
(100). The room temp. Current-voltage characteristics
were obtained to access the quality of deposited thin
films. The forward bias current-voltage characteristics
were measured and fitted to the equation


/1
av
o
JJe nKT

 (1)
where J is the current density in amps/cm2 and n is ideal-
ity factor of the diode. When n is close to unity, the re-
sults of thermonic emission theory are valid such that,
** 2/
K
T
o
JATe

 (2)
where A** is the modified Richardson constant in
amp/cm2 and Φ – Barrier height.
The saturation current density Js is given by
2
*exp
s
qBn
JAT kT





(4)
The parameter n is given by
1
(ln *)
1kT A nVq V



  
 




 (5)
where

is the height of Schottky barrier,


is the
Schottky barrier lowering and A* is the effective Rich-
ardson constant.
For the annealing temperature at 300 and 600℃ of
BaTiO3/Si shows the ideality factor was found to be varying
Figure 5. I – V Characteristics of a Typical diode with 90 Ao
thick BaTiO3 film on Si (100) with annealed at (A) 300℃
and (B) 600℃.

Synthesis and Electrical Characterization of BaTiO3 Thin Films on Si(100) 190
between 1.2 to 1.1. The value of n = 1 is consistent with
current injection through a shottkey barrier, While large
value indicates conduction by generation recombination.
A Poor ideality factor can have variety of interpretation
among them, the effect of Tunneling can be excluded
because of low carrier density in substrates. The ideality
factor decreases with increasing annealing temp. of Ba-
TiO3/Si as shown in Figure 5.
These results show that the electrical properties of Ba-
TiO3/Si, MIS structure improved at higher annealing
temp.
4. Conclusions
BaTiO3 thin film has been synthesized using sol-gel
process and deposited on Si (100) by using spin – coating
technique. The BaTiO3/Si(100) structures were studied
by structural and electrical characteristics. The XRD and
SEM of BaTiO3/Si(100) indicates the enhance crystallin-
ity of the films with annealing temperature at 600℃. The
C-V measurement of BaTiO3 thin film deposited on
Si(100) annealed at 600℃ shows large frequency disper-
sion in the accumulation region. The current-voltage
measurement of BaTiO3/Si shows the ideality factor was
approaches to unity at 600℃.
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