Influence of the oxygen on the
optical properties of RF-sputtered
Zinco-Oxide thin films
Mariano Gioffrè(2), Massimo Gagliardi (1) (2), Massimo
Angeloni(1), Mario Iodice(3), Giuseppe Coppola(1) and
Ivo Rendina(1)
(1)Institute for Microelectronics and Microsystems
National Council of Research (IMM-CNR), Naples, Italy
(2) Mediterranea University of Reggio Calabria, Italy
Riunione Annuale GE 2006
Ischia, 21-23 giugno 2006
ZnO
ellipsometric model
3
void.dsp
2
ZnO.dsp
fit results
ZnO.dsp
1
ZnO.dsp
void.dsp
S
glass.dsp
0.600
0.350
0.550
0.300
0.500
0.250
0.200
0.450
0.150
0.400
0.100
Ic
Dispersion model of ZnO: Tauc-Lorentz single oscillator
[4,5]
 1 A  E0  C  ( E  Eg )

2
2 2
2
2
immaginary part of dielectric
 E ( E  E0 )  C  E

function:
2  

0


0.050
0.300
0.000
2
real part from KramerKroning relation:
0.250
E  Eg
E  Eg
Dispersion model of glass: Forouhi & Bloomer
[7, 8]

Fitting parameters : g , f j ,  j ,  j , n
Riunione Annuale GE 2006
-0.050
0.200
-0.100
0.150
-0.150
0.100
-0.200
400

    
2
1      P  2 2 2 d
 Eg   E
Fitting parameters: E0, Eg, A, C,  [6]
Is
0.350
500
600
700
800
900
1.000 1.100
Wavelength (nm)
1.200
1.300
1.400
1.500
1.600
X2 = 0.32
References:
[4] H. G. Tompkins, W. A. McGahan, "Spectroscopic Ellipsometry and
Reflectometry ", Ed.John Wiley & Sons
[5] G. E. Jellison and F. A. Modine, Appl. Phys. Lett. 69, 371 (1996)
[6] G. E. Jellison, F.A. Modine, P. Doshi, A. Doshi, A. Rohatgi, Thin Solid
Films, 313-314, 195 (1998)
[7] A.R. Forouhi, I.Bloomer, Phys.Review B 34, 7018-7026 (1986)
[8] A.R.Forouhi, I.Bloomer, Phys.Review B 38, 1865-1874 (1988)
Ischia, 21-23 giugno 2006
Refractive index
Refractive index
Sputtering deposition parameters
Samp
le
Po
wer
(W)
Temperatur
e (0C)
Flow argon
(sccm)
Flow
oxigen
(sccm)
Pressure
(mbar)
Time
(min)
1
200
50
40
10
0.02
12
2
200
50
40
6
0.02
12
3
200
50
40
3
0.02
12
4
200
50
40
0
0.02
12
The resullts of fitting parameters for sample 1
sample
1
2
3
4
Eg
3.217
0.004
3.22  0.01
3.218
0.004
3.296
0.005
Wavelength (nm)
Comparison between measured and simulated transmittance
The obteined index refractive is in good agreement with
literature[9,10]
1.0
Trasmittance
0.8
0.6
References:
Spectrofotometer
Ellipsometer
0.4
[9] E. Dumont, B. Dugnoille, S. Bienfait,
Thin Solid Films, 353, 93 (1999)
0.2
0.0
400
600
800
1000
1200
1400
1600
Wavelenght (nm)
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GE 2006
[10] W. L. Bond, J. Appl. Phys. 36, 1674
(1965) Ischia, 21-23 giugno 2006