UGC-DAE Consortium for scientific Research
New Versatile facility at UGC-DAE CSR, Indore
In-situ thin film Lab
Strength and Capabilities
 In-situ characterization
techniques
i. Magneto optical Kerr effect
(MOKE)
ii. Magnetoresistance (MR)
iii. Small angle X-ray reflectivity
(XRR)
iv. Reflection high energy electron
diffraction (RHEED)
 Deposition using e-beam
evaporation
Magnetic field for MOKE ~0.25 T
Sample temperature ranging
from ~50K to 1200K
RHEED: 30 KeV electron gun
Other important points
 Base
pressure
in
the
UHV
chamber ~2x10-10 mbar
 Sample temperature ranging from
~50K to 1200K, which can be
precisely controlled during all in- Chamber is equipped with a facility for thin film deposition using
electron beam evaporation with in-situ measurement of magneto
optical Kerr effect (MOKE), reflection high energy electron diffraction
(RHEED) and magnetoresistance (MR) measurements.
-Whole set-up is attached with a lab x-ray source coupled with a
multilayer optics, which provides a beam of sufficient collimation and
intensity to perform in-situ small angle x-ray reflectivity (XRR) experiments
in the laboratory.
-All the measurements in the present system can be done simultaneously
during and after the deposition of the film, thus making it possible to
study the evolution of magnetic, transport and structural properties with
parameter such as film thickness, annealing temperature etc.
-In contrast to the earlier in-situ systems in the literature, where
measurements with each technique are performed separately and
results are interpreted by combining the data, in the present set-up,
combination of these techniques as in-situ measurements seems to be
promising in surface and interface analysis of magnetic thin films and
multilayer nanostructures.
Page 1
situ measurements
 Ion gun at an oblique angle for
sample cleaning
 Residual gas analyzer (RGA) to
monitor residual gasses present
before and during the deposition
 Mass flow controller to create
partial pressure of the gases such
as O2 N2 Ar etc.
Dr. Dileep K. Gupta
Scientist
In-situ thin film Lab
UGC-DAE CSR, Indore-452001
dkumar@csr.res.in;
dileep.esrf@gmail.com
Phone: +91-731-2463913 (ext.176)
To use other facilities at the center visit: http://csr.res.in
An illustration of the versatility of the set-up
In-situ thin film Lab
 In-situ MOKE, RHEED and XRR measurements of Co/CoO bilayer during Growth
Co/CoO bilayer structure was grown in UHV chamber at the base pressure of ~10-10 mbar using e-beam
evaporation technique. Growth of the bilayer sample was done on a silicon substrate in two steps; (i) deposition
of Co film at room temperature (ii) and formation of uniform oxide layer at the surface by heating it at 3000C in
a partial oxygen pressure 5 ×10-6 mbar.
During the growth of the bilayer, magnetic and structural properties were investigated in-situ using magnetooptical Kerr effect (MOKE), Reflection high energy electron diffraction (RHEED) and X-ray reflectivity (XRR)
measurements.
10
Intensity (a.u)
5
X-Ray Intensity (a.u.)
Co film
as prepared
Co on Si
Si Subs
4
10
0, 45, 90 degree
3
10
-150 -100
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6
-50
RHEED image of Co
0
50
100
150
H(Oe)
Angle (Theta)
15 min
Loop measurements
during surface oxidation process
25 min
10 min heating
50 min heating
35 min
Intensity (a.u)
Reflectivity (arb. units.)
As prepared
50 min
60 min
75 min
75 min heating
0.4
RHEED image of top CoO layer
0.8
1.2
2 theta
1.6
2.0
2.4
-150
-100
-50
0
50
100
150
H (Oe)
First row: RHEED, XRR and MOKE measurements after deposition of Co film on Si substrate. Hysteresis
loops in the last figure are taken at different azimuthal angle to get information of magnetic
anisotropy in the Co film.
Second raw: all above mentioned measurements after surface oxidation of Co film. XRR and MOKE
measurements were carried also out during process of oxidation (after different time interval).
It may be noted that MOKE and XRR measurements can be performed simultaneously whereas RHEED
measurements is performed after MOKE measurement in order to avoid deflection in electron due to magnetic
field generated by electromagnet during MOKE measurements.
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An illustration of the versatility of the set-up
In-situ thin film Lab
 Effect of Substrate Roughness on Growth of Thin Nanocrystalline Cobalt film
Growth of Co film on glass substrates with surface roughness of
0.5 nm and 1.6 nm has been studied in-situ using magnetooptical Kerr effect (MOKE), reflection high energy electron
diffraction (RHEED) and four probe resistivity methods.
0.9 nm
(d)
(e1)
2.5 nm
(d1)
2.4 nm
sub= 0.5 nm
1.4
RCo (k/k)
1.1 nm
(e)
1.6
Variation of sheet
resistance as a
function of Co
growth on rough
and
smooth
substrate
(B)
(A)
sub= 1.6 nm
1.2
(c1)
0.7 nm
(c)
1.0
2.2 nm
0.8
(b1)
(b)
0.6
2.0 nm
0.5 nm
0.4
0.2
(a)
0.0
(a1)
1.8 nm
0.0
0.5
1.0
1.5
2.0
2.5
Substrate
3.0
d (nm)
-110 -55
Representative loops with increasing Co layer thickness on [A]
=0.5nm and [B] =1.6nm substrate
0
-110 -55
55 110
0
55 110
H (Oe)
H (Oe)
In-situ measurements jointly suggested that the films grow via Volmer-Weber growth process and proceed via
a nonmagnetic, superparamagnetic and a ferromagnetic phase on both the substrates. Islands were found
to coalesce at film thicknesses of ~ 0.6 nm and at ~ 1.5 nm for smooth and rough substrate respectively and
films become continuous and fully covering after the film thickness of ~1.5 nm and ~ 3.0 nm.
 Thermal stability of W/Si and W/B4C/Si multilayers:
In order to study the mechanism of diffusion in W/Si and W/B4C/Si multilayer, in-situ XRR measurements were
carried out upto high temperature annealing under UHV conditions. The temperature of the samples was
increased in the steps of ~200C from 2000C to 8000 C.
Sample structure
NOTE: These samples were prepared using
ion beam sputtering technique in a
different chamber and finally transferred to
the UHV system for in-situ reflectivity.
Page 3
X-Ray Intensity (a.u.)
It may be note that in case of W/B4C/Si
multilayer the height of the Bragg peak
does not change significantly even up to
8000C, whereas as in case of W/Si multilayer
it is significantly influenced after thermal
annealing. The present measurements
revealed that the addition of very thin layer
of B4C at interface of W and Si reduces interdiffusion between W and Si significantly.
W/Si Multilayer
W/B4C/Si Multilayer
X-Ray Intensity (a.u.)
1. Si substrate W /B4C/Si- 10 bilayers
– bilayer thickness 4.3 nm
2. Si substrate W (1.7nm)/Si(2.4 nm)10 bilayers- bilayer thickness 4.1nm
0.0
0.4
0.8
1.2
1.6
Angle (Theta)
2.0
2.4
0.0
0.4
0.8
1.2
1.6
2.0
2.4
Angle (Theta)
In-situ XRR pattern of a) W/B4C/Si multilayer and b) W/Si
multilayer at various temperatures ranging from 2000C to 8000C
An illustration of the versatility of the set-up

In-situ thin film Lab
Attachment of Magneto-resistance (MR) option; growth of Ni film of Si substrate
In order to perform in-situ transport measurements, sample holder for four probe resistivity measurement has
been modified and tested by performing resistivity measurement during growth of Ni film. MR measurements
were also performed with increasing thickness of Ni layer. Experiments performed are shown below.
Schematic view of sample holder prepared
Thin film
Au contacts
d= 20nm
0
300
H (Oe)
0.4
0.2
0
H (Oe)
Continious film
Island film
0
-300 0 300
H (Oe)
Connecting islands
Resistance (k-ohm)
-300
0.6
4
8
12
16
20
d (nm)
Resistance and MOKE with Ni growth up
to 20 nm thickness
Voltage of the sample(V)
d= 2nm
d= 0.5nm
0.8
0
0
30
10
0
60
-225
0
40
0
0
70
0
20
50
0
225 -225
80
0
225
0
0
0
-225
0
225
Magnetic Field(Oe)
Magneto-resistance of Ni 20 nm thin film at
different azimuthal angle
First figure gives the thickness dependence of film resistance (R). Initially up to a thickness of about 1.5 nm the
sheet resistance remains almost constant and essentially represents resistance of Si substrate. At this thickness,
the separation between Ni islands would be quite large and the conduction of electrons from one island to
another will not take place. With further increase in the thickness, as the islands come closer, hopping conduction
can take place, which results in a gradual decrease in the sheet resistance with thickness. Around a thickness of
about 2 nm a rapid decrease in the resistivity is observed, which signals the formation of a percolating cluster. In
the thickness range of 12–15 nm a continuous film is formed, and beyond this resistance exhibits a slow decrease
because of decreasing contribution of surface and interface scattering. Inset of Figure represents hysteresis loops
of Ni thin film at film thickness of 0.5, 2 nm and 20nm. One may note that at a thickness of 0.5 nm, hardly any loop
developed whereas a faint hysteresis loop starts appearing at around 2 nm thickness. The combined information
with MOKE revealed that near the film thickness of 2-3 nm, as the islands become multi-domain, the coercivity
starts developing. At very low thickness loop may be absent due to very small islands, which may be in single
magnetic domain and exhibit superparamagnetism. The present set-up also provides the capability to do MR
measurements at different azimuthal direction by rotating sample holder between the poles of the magnetic
field. Magneto-resistance (MR) measurements at thickness of 20 nm are also shown in figure.
Page 4
Related Publications
In-situ thin film Lab
1. “Interface induced perpendicular magnetic anisotropy in a Co/CoO/Co thin-film structure: an in situ
MOKE investigation”
Dileep Kumar, Ajay Gupta, P. Patidar, A Banerjee, K K Pandey, T. Sant and S. M. Sharma, J. Phys. D: Appl.
Phys. 47 (2014) 105002; doi:10.1088/0022-3727/47/10/105002
2. “In situ surface magneto-optical Kerr effect (s-MOKE) study of ultrathin soft magnetic FeCuNbSiB alloy
films”
Dileep Kumar, Pooja Gupta, and Ajay Gupta, Materials Research Express 1 (2014) 046405;
doi:10.1088/2053-1591/1/4/046405.
3.
“Correlation between iron self-diffusion and thermal stability in doped iron nitride thin films”
Akhil Tayal, Mukul Gupta, Dileep Kumar, V. R. Reddy, Ajay Gupta, S. M. Amir, Panagiotis Korelis, and
Jochen Stahn, Journal of Applied Physics 116, 222206 (2014); doi: 10.1063/1.4902962.
4. “Study of ultrathin magnetic cobalt Films on MgO(001)” Gagan Sharma, U.P. Deshpande, Dileep Kumar
and Ajay Gupta Journal of Applied Physics 112, 023910 (2012).
5. “In-situ study of magnetic thin films on nanorippled Si (1 0 0) substrates”
Sarathlal K.V., Dileep Kumar, V. Ganesan, Ajay Gupta, Applied Surface Science 258 (2012) 4116
6. “Study of Co90Fe10 magnetic thin Film on MgO substrate using In-situ MOKE Technique”
Gagan Sharma, Dileep Kumar, Ajay Gupta
Journal of Physics: Conference Series 365 (2012) 012038
7. “Growth study of Co thin film on nanorippled Si(100) substrate”
Sarathlal K. V., Dileep Kumar, and Ajay Gupta, Appl. Phys. Lett 98, 123111 (2011)
Dr. Dileep K. Gupta
Scientist
In-situ thin film
UGC-DAE CSR, Indore-452001
dkumar@csr.res.in; dileep.esrf@gmail.com
Phone: +91-731-2463913 (ext.176)
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