si x ge 1-x and si x ge 1-x o y films as a thermal sensing material
DESCRIPTION
Si x Ge 1-x and Si x Ge 1-x O y Films as a Thermal Sensing Material. Mukti Rana and Donald Butler University of Texas at Arlington Electrical Engineering Dept. Arlington, TX 76019 Based in part by work supported by the National Science Foundation ECS-0322900. - PowerPoint PPT PresentationTRANSCRIPT
SixGe1-x and SixGe1-xOy Films as a Thermal Sensing Material
Mukti Rana and Donald Butler
University of Texas at Arlington
Electrical Engineering Dept.
Arlington, TX 76019
Based in part by work supported by the National Science Foundation ECS-0322900
SixGe1-x and SixGe1-xOy Films as Sensing Material
• Both SixGe1-x and SixGe1-xOy are conventional semiconductors
• High TCR (~-5%/K) can be obtained with moderate resistivity value (~104 ohm-cm) from a suitable combination of SixGe1-xOy
• Iborra et. al (2002) reported a TCR of
-4.21%/K from RF Sputtered SixGe1-xOy
• García et. al (2004) reported a TCR of -5.1%/K from PECVD a-Si1-xGex:H,F.
Deposition: SixGe1-x and SixGe1-xOy Films
• Cosputtering from Ge + Si regions target.
• RF magnetron Sputtering at 160 W and 10 mTorr pressure.
• SixGe1-x deposited in Ar environment.
• SixGe1-xOy deposited in Ar:O environment.
Resistivity: SixGe1-x
0 10 20 30 40 500
2
4
6
8
10R
esis
tivity
(1
03
-c
m)
Silicon concentration (at. %)
TCR and Activation Energy (Ea)KT
Ea
eRR
0
0
5 108
1 109
1.5 109
2 109
2.5 109
3 109
3.5 109
4 109
-9
-8
-7
-6
-5
-4
180 200 220 240 260 280 300 320 340
Resistance
TCR
Res
ista
nce
()
TC
R (%
/K)
Temperature (K)
TCR and Activation Energy: SixGe1-x
2
2.5
3
3.5
4
4.5
0.1
0.15
0.2
0.25
0.3
0 5 10 15 20 25 30 35 40
TCR (%/K)
Activation Energy (eV)
0 5 10 15 20 25 30 35 40
TC
R (
%/K
)A
ctivation energy (eV)
Silicon concentration (at. %)
Optical Bandgap: SixGe1-x
0.8
0.9
1
1.1
1.2
1.3
0 10 20 30 40 50
Opt
ical
ban
dgap
(eV
)
Silicon concentration (at. %)
Resistivity: SixGe1-xOy
1000
104
105
106
107
108
109
1010
0 5 10 15 20
15% Silicon
30% Silicon
40% Silicon
0 5 10 15 20
Res
istiv
ity
(-c
m)
Oxygen concentration (at. %)
Activation Energy: SixGe1-xOy
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0 5 10 15 20
15% Silicon
30% Silicon
40% Silicon
Act
ivat
ion
ener
gy (
eV)
Oxygen concentration (at. %)
TCR: SixGe1-xOy
2
3
4
5
6
7
8
9
0 5 10 15 20
15% Silicon
30% Silicon
40% Silicon
0 5 10 15 20
TC
R (
%/K
)
Oxygen concentration (at. %)
Noise PSD: Si0.15Ge0.85Oy @ 1.79 μA Bias Current
10-13
10-12
10-11
10-10
10-9
10-8
10-7
1 10 100 1000 104 105
y = 0
y = 0.0309
y = 0.034
1 10 100 1000 104 105
Noi
se V
otag
e P
SD
[V
2 /Hz]
Frequency [Hz]
Transmittance: Si0.15Ge0.85Oy
0
20
40
60
80
100
120
500 1000 1500 2000 2500 3000
9% Oxyzen5.5% Oxyzen3.8% Oxyzen3.46% Oxyzen3% Oxyzen0% Oxyzen
Tan
smit
tanc
e (%
)
Wavelength (nm)
Optical Bandgap: SixGe1-xOy
0.6
0.8
1
1.2
1.4
1.6
1.8
0 5 10 15 20
15% Silicon
30% Silicon
40% Silicon
0 5 10 15 20
Opt
ical
ban
dgap
(eV
)
Oxygen concentration (at. %)
X-ray Diffraction (XRD) Pattern for Si0.125Ge0.8365O0.039
0
50
100
150
200
250
0 10 20 30 40 50 60
Inte
nsit
y (a
rb. u
nits
)
2 (deg.)
Energy Dispersive X-Ray Analysis of Si0.1188Ge0.8472O0.034
Film By Scanning Electron Microscope (SEM)
Transmittance: SixGe1-x
0
20
40
60
80
100
120
140
500 1000 1500 2000 2500 3000
0% Silicon15% Silicon30% Silicon40% Silicon
Tra
nsm
itta
nce(
%)
Wavelength (nm)
Transmittance: Glass Substrate used for Depositing SixGe1-xOy and SixGe1-x Thin Films
40
50
60
70
80
90
100
110
120
500 1000 1500 2000 2500 3000
% T
ran
smis
sion
Wavelength
SixGe1-xOy and SixGe1-x : Normalized Hoogie Coefficient for 1/f-noise (αH/N) determined at 10 Hz frequency and other
propertiesSAMPLE Normalized Hooge
parameterαH/N
TCR(%/K)
Activation Energy (Ea)
(eV)
Optical Bandgap (Eg) (eV)
Si0.15Ge0.85 1.70 × 10-10 4.2 0.264 0.91
Si0.099Ge0.871O0.031 4.3 × 10-11 4.4 0.297 0.80
Si0.118Ge0.847O0.034 1.10 × 10-10 4.6 0.310 0.81
Si0.125Ge0.8365O0.039 < 2.58 × 10-8* 5.1 0.324 0.89
Si0.114Ge0.834O0.052 < 2.35 × 10-6* 5.7 0.368 0.89
Si0.172Ge0.736O0.092 < 4.06 × 10-3* 6.7 0.453 1.4
Si0.294Ge0.706 9.55 × 10-11 3.2 0.181 0.89
Si0.269Ge0.692O0.039 3.12 × 10-8 3.5 0.191 0.75
Si0.281Ge0.628O0.092 < 4.17 × 10-4* 4.9 0.336 1.1
Si0.269Ge0.579O0.152 < 3.62 × 10-4* 7.3 0.577 1.2
Si0.427Ge0.573 < 5.08 × 10-10* 2.3 0.138 0.89
Si0.386Ge0.599O0.015 2.45 × 10-10 2.6 0.155 0.86
Si0.425Ge0.524O0.052 < 4.19 × 10-9* 3.4 0.222 0.86
Si0.380Ge0.525O0.095 < 3.36 × 10-7* 4.7 0.304 0.83
Si0.411Ge0.421O0.168 < 1.30 × 10-4* 8.7 0.658 0.87
Ge 2.07 × 10-10 3.7 0.296 0.96
fN
RIS bHv
22