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119-10-2004 E.Vittone, IEEE-RTSD, ROME
Silicon Carbide for Alpha, Beta , Proton and Soft X-Ray High Performance Detectors
Ettore Vittone Experimental Physics Department, University of
Torino, Italy
INFM
INFN
219-10-2004 E.Vittone, IEEE-RTSD, ROME
Talk OutlineTalk Outline
•Motivations
•4H-SiC Schottky diode manufacture
•Characterisation and performances
•X-rays
•MeV Ions
•Beta particles
•Radiation damage
•Neutrons
•Conclusions
Silicon Carbide for Alpha, Beta , Proton and Soft X-Ray High Performance Detectors
319-10-2004 E.Vittone, IEEE-RTSD, ROME
Physics Dept., University of Modena (F.Nava)
Experimental Physics Dept. University of Torino (E.Vittone)
Elect Engn & Informat Sci. Dept., Politecnico of Milano (G.Bertuccio)
Physics Dept., University of Bologna (A.Cavallini)
Material Science Dept., University of Milano (S.Pizzini)
Dipartimento di Energetica, University of Florence (S.Sciortino)
Alenia Marconi Systems, Roma (I) (C.Lanzieri)
Institute of Crystal Growth (IKZ),, Berlin, (D) (G.Wagner)
INFM
INFN
PARTNERS
CERN RD50: Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders
N37 Radiation Damage Effects I - Solid State, Wednesday, October 20, Spalato
M. Bruzzi, INFN Firenze, Italy, “On behalf of the CERN RD50 Collaboration”
419-10-2004 E.Vittone, IEEE-RTSD, ROME
SiC material from CREE
ND-NA=6.8·1018 cm-3
ND-NA=1.0·1018 cm-3
ND-NA=2.2·1015 cm-3
Substrate
Buffer layer
Epitaxial layer
519-10-2004 E.Vittone, IEEE-RTSD, ROME
Problems and drawbacks
• thin depletion layer widths
• defects at the interface of epilayers
• contacts technology and surface treatments
• large band gap (3.3 eV) and very low dark current
• high carrier saturation velocity
• high breakdown electrical field
• large thermal conductivity
• satisfactory electrical homogeneity
PROPERTY 4H-SiC Si GaAs Diamond Band Gap (eV) 3.3 1.12 1.43 5.5
Room Temperature e / h
800/115 1350/480 8500/400 1800/1200
Saturation drift velocity of electrons (107cm/s) 2.0 0.8 0.8 2.2
Max electric field (105V/cm) 40 3 4 100
Average energy for e-h pair (eV)
8.4 - (7.8) 3.62 4.21 13-17
e-h pairs/m for MIPs 5100 9000 13000 3600
Density (g/cm3) 3.2 2.33 5.32 3.5
Z 14/6 14 31/33 6
Thermal conductivity (W/cmK) 4.9 1.5 0.5 20
Dielectric constant 9.7 11.9 13.1 5.7
Mono-crystalline yes yes yes No-(Yes)
Wigner Energy (eV) 25 13-20 10 43
Good Bad
619-10-2004 E.Vittone, IEEE-RTSD, ROME
Small Effect of Temperature on Current
Lowest Leakage Currents
Silicon Carbide Detector Advantages
G.Bertuccio
Politecnico Milano(2001)
0,1 1 10 10010-14
10-12
1x10-10
1x10-8
1x10-6
10-14
10-12
1x10-10
1x10-8
1x10-6
CdZnTe
4H-SiC (Epi)
Room Temperature
CdTe
GaAs (VPE)
GaAs (SI LEC)
Silicon
Cur
rent
den
sity
[ A
/ cm
2 ]
Mean electric field [ kV / cm ]
Si1 nA/cm2
SiC5 pA/cm2200
Si1 nA/cm2
Si1 nA/cm2
SiC5 pA/cm2200
SiC5 pA/cm2
SiC5 pA/cm2200
1 10 100 20010-12
10-11
1x10-10
1x10-9
1x10-8
1x10-7
(19 nA/cm2)
(1 nA/cm2)
(5 pA/cm2)
(17 pA/cm2)
1000
200340 K
340 K
300 K
300 K
Curr
ent densi
ty [ A
/cm2 ]
Mean electric field [ kV/cm ]
Si
4H-SiC
1 10 100 20010-12
10-11
1x10-10
1x10-9
1x10-8
1x10-7
(19 nA/cm2)
(1 nA/cm2)
(5 pA/cm2)
(17 pA/cm2)
1000
200340 K
340 K
300 K
300 K
Curr
ent densi
ty [ A
/cm2 ]
Mean electric field [ kV/cm ]
Si
4H-SiC
719-10-2004 E.Vittone, IEEE-RTSD, ROME
DIODE MANUFACTURE
819-10-2004 E.Vittone, IEEE-RTSD, ROME
SUBSTRATE
360 m n-type 4H-SiC by CREE CREE (USA)
SMP quality: 16-30 micropipes/cm2
LMP quality: 15 micropipes/cm2
off-oriented 8° towards 1120
919-10-2004 E.Vittone, IEEE-RTSD, ROME
Günter Wagnerhttp://rd50.web.cern.ch/RD50/2nd-workshop/
EPITAXIAL LAYER
Epitaxial wafers purchased from CREE Research. Thickness 30-70 m
Institute of Crystal Growth (IKZ), Berlin, Germany (G.Wagner)
1019-10-2004 E.Vittone, IEEE-RTSD, ROME
SMP waferEpilayer thickness: 48.0 ± 0.6 m
LMP waferEpilayer thickness: 48.9 ± 0.8 m
Institute of Crystal Growth (IKZ), Berlin, Germany (G.Wagner)
SMP
LMP
Lateral view
EPITAXIAL LAYER
1119-10-2004 E.Vittone, IEEE-RTSD, ROME
SCHOTTKY DIODE
Alenia Marconi Systems, Roma (I) (C.Lanzieri)
Si-face
Ohmic contact over all the backside of the substrate (C-face): deposition of a multilayer of Ti/Pt/Au (30/30/150 nm) followed by an annealing at 1000°C for 1 min in N2/H2
atmosphere.
Schottky contact:
Cleaning: sputtering with 200 eV argon ions to remove a thin film of 20 nm on the Si surface of the epilayer; dip in a 10:1 diluted HF solution for 1 min; water rinse; nitrogen blow dry.
Deposition: Ni (or Au) was evaporated from an e-gun heated source to a thickness of 200 nm. Circular Ni (or Au) diode dots with a diameter of 1.5,3,5 mm and a guard ring, were obtained using a standard lithography techniques featuring lift-off steps.
Annealing (for Ni only): at 800°C for 1 min in N2/H2 atmosphere for the silicide formation
(Ni2Si) as identified to be by using the X-ray
diffraction technique.
1219-10-2004 E.Vittone, IEEE-RTSD, ROME
CHARACTERISATIONR11 RTSD Poster Session, Thursday, October 21 11:00-12:30, Pola
G. Bertuccio, S. Binetti, S. Caccia, R. Casiraghi, A. Castaldini, A. Cavallini, C. Lanzieri, A. Le Donne, F. Nava, S. Pizzini, E. Vittone
“Physical and Electrical Characterisation of Silicon Carbide for Room and High Temperature Radiation Detectors”
1319-10-2004 E.Vittone, IEEE-RTSD, ROME
C-V
0 5 10 15 20 25 30 35 401x1014
2x1014
3x1014
4x1014
5x1014
6x1014
7x1014
8x1014
9x1014
Do
pin
g c
on
cen
trat
ion
[cm
-3]
Depth [m]
Epilayer from IKZ; Thickness 40 m
I-V
1419-10-2004 E.Vittone, IEEE-RTSD, ROME
[1] F. Nava et al. Nuclear Instruments and Methods in Physics Research A 437 (1999) 354[2] A.Castaldini et al. Applied Surface Science 187 (2002) 218-252[3] F. Nava et al. Nuclear Instruments and Methods in Physics Research A 505 (2003) 645[4] M.Bruzzi et al. Diamond and Related Materials 12 (2003) 1205[5] G.Bertuccio et al. Nuclear Instruments and Methods in Physics Research A 522 (2004) 413–419[6] F.Nava et al. , IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 51, NO. 1, FEBRUARY 2004, pag 241[7] A. Lo Giudice et al. to be published
Epilayer Thickness
(m)
Electrode area(cm2)
Electrode
ND
(cm-3)
Js
(pA/cm2)
qbn
(eV)
From I-V
From C-V
CREE [1,3]
30 3.110-2 Au 2.21015 1.19 1.7
CREE [2]
30 3.110-2 Au 2.01015 1.18 1.38
CREE [3]
30 3.110-2 Au 2.51015 1.03 1.03
CREE [4]
50 3.110-2 Au 9.41014 510-11 @ 500 V
CREE [5]
70 3.010-4 -1.210-2
Au 91014 510-13 @ 500 V
1.2
IKZ [6] 40 1.810-2 Ni2Si 4.7-7.71013
3510-10 @ 400 V
1.05 1.77 1.84
IKZ [7] 40-50 7.010-2 Ni 1.71014 510-12 @ 200 V
1.25 1.43 1.75
1519-10-2004 E.Vittone, IEEE-RTSD, ROME
X-Y Scanning system
Quadrupolefocussing lenses
Sample holder
Analysis chamber
X
ZIon
Beam
Nuclear Microprobe at the Laboratory for Ion Beam InteractionsRudjer Boskovic Institute , Zagreb (HR)
Sample
Vbias
Charge sensitivepre-amplifier
Amplifier
Electrode
X
YX-Y Scanning system
Quadrupolefocussing lenses
Sample holder
Analysis chamber
X
ZIon
Beam
Nuclear Microprobe at the Laboratory for Ion Beam InteractionsRudjer Boskovic Institute , Zagreb (HR)
Sample
Vbias
Charge sensitivepre-amplifier
Amplifier
Electrode
X
Y
Sample
Vbias
Charge sensitivepre-amplifier
Amplifier
Electrode
X
Y
IBICCIon Beam Induced Charge Collection
Microscopy
Experimental Physics Dept., University of Torino, (I)
1619-10-2004 E.Vittone, IEEE-RTSD, ROME
The CCE response is homogeneous for low energy ions where ionisation occurs in the depletion region.
More pronounced CCE inhomogeneities in proximity of the
buffer layer
contact scratches
silver paste
Damaged region inducedby 2 MeV Li irradiation (penetration = 3.1 m)
Bulk defects
contact scratches
silver paste
Damaged region inducedby 2 MeV Li irradiation (penetration = 3.1 m)
Bulk defects
1719-10-2004 E.Vittone, IEEE-RTSD, ROME
X
Y Z
S ample
V bias
E lect r ode
Keit hley 617picoamper omet er
O ndulatorCrystal
monochromatorZ one plate
obj ect ive lens
A perture Raster X - Ypiezo scanner
ID21 sc anning x-ray mic rosc ope (SXM )ESRF - Grenoble (F )
3 keV x-ray energy; about 10 photons/s;8
Spot size about 1 mAttenuation length in S iC : 4 mAu contact (100 nm th ick): attenuation 33%
W ireElectrode
Silver drop
15
10
5
0
Photocurrent(nA)
0
1E-4
2E-4
3E-4
4E-4
5E-4
6E-4
7E-4
8E-4
9E-4
1E-3
0,00
0,00
0,00
0,00
0,00
0,00
0,00
1,1 1,2 1,3 1,4 1,5 1,6 1,7 1,8 1,9 2,0
1,6
1,5
1,4
1,3
1,2
1,1
1,0
0,9
0,8
0,7
(1,05;0,655)
X Axis (mm)
- 50 V
Y A
xis
(mm
)
XBICCX-ray Beam Induced Charge Collection Microscopy
10 20 30 40 50 60 70 80 90 100
10
20
30
40
50
60
70
80
90
100
V = -50 V
X Axis (m)
Y A
xis
(m
)
23.0023.6924.3825.0625.7526.4427.1327.8128.5029.1929.8830.5631.2531.9432.6333.3134.00
Experimental Physics Dept., University of Torino, (I)
1819-10-2004 E.Vittone, IEEE-RTSD, ROME
Optical microscope image
XBIC map of two electrodes XBIC profile
1919-10-2004 E.Vittone, IEEE-RTSD, ROME
DLTS and isothermal capacitance transient spectroscopy (ICTS)
Physics Department, University of Bologna, (I)
(A.Cavallini)
N Cr/Ti Related to O
DLTS at different polarisation conditions todistinguish between in-depth and surface located levels
2019-10-2004 E.Vittone, IEEE-RTSD, ROME
DETECTOR PERFORMANCES
2119-10-2004 E.Vittone, IEEE-RTSD, ROME
Room and High Temperature X-ray Spectroscopy
SiC Detector at 27°C
0 5 10 15 20 25 30
101
102
103
Np L - X rays
11.8
9.76.4
20.8
13.917.7 keV
3.3 keV
26.3
241Am
SiC Pixel DetectorV
bias=200 V
shaping: 6s
Cou
nts
Energy [ keV ]
Dept of Electronics Engineering and Information Science, Politecnico di Milano, (G.Bertuccio)
Pixel Area = 0.31 mm2
Schottky contact - Au
n - epilayer 5.3x1014 - 70 m
n+ buffer 1 m
n+ substrate
ohmic contact -Ti/Pt/Au
Schottky contact - Au
n - epilayer 5.3x1014 - 70 m
n+ buffer 1 m
n+ substrate
ohmic contact -Ti/Pt/Au
purchased from CREE Research
Noise level = 315 eV FWHM
2219-10-2004 E.Vittone, IEEE-RTSD, ROME
40 80 120 160 20010-15
1x10-14
1x10-13
1x10-12
1x10-11
107 °C
87 °C
67 °C47 °C
27 °C
Rev
erse
Cur
rent
[ A
]
Reverse Voltage [ V ]
10-12
10-11
1x10-10
1x10-9
Cur
rent
Den
sity
[ A
/cm
2 ]
Reverse I-V
0.0 0.2 0.4 0.6 0.8 1.010-15
1x10-13
1x10-11
1x10-9
1x10-7
1x10-5
1x10-3
t=127°C
t=47°C
t=67°C
t=87°C
t=107°C
t=24°C
Forward Voltage [ V ]
Fo
rwa
rd C
urre
nt [
A ]
b=1.16 eV
Forward I-V
0.0 0.2 0.4 0.6 0.8 1.010-15
1x10-13
1x10-11
1x10-9
1x10-7
1x10-5
1x10-3
t=127°C
t=47°C
t=67°C
t=87°C
t=107°C
t=24°C
Forward Voltage [ V ]
Fo
rwa
rd C
urre
nt [
A ]
b=1.16 eV
Forward I-V
0 5 10 15 20
2x1014
4x1014
6x1014
8x1014
1x1015
Conduct
ion e
lect
ron
conce
ntr
atio
n [ c
m-3 ]
Distance from junction [ m ]
<n> = 5.3x1014 cm-3
Pixel Area = 0.31 mm2
Current Density of 4H-SiC junctions:
< 6 pA/cm2 up to 100kV/cm (200V) at 24°C
< 0.9 nA/cm2 up to 100kV/cm (200V) at 107°C
Room and High Temperature X-ray Spectroscopy
2319-10-2004 E.Vittone, IEEE-RTSD, ROME
SiC Detector at 100°C
0 5 10 15 20 25 30
102
103
104
Np L - X rays
11.8
9.76.4
20.8
13.917.7 keV
3.3 keV
26.3
241Am
SiC Pixel DetectorV
bias=200 V
shaping: 4s
Cou
nts
Energy [ keV ]
SiC Detector at 27°C
0 5 10 15 20 25 30
101
102
103
Np L - X rays
11.8
9.76.4
20.8
13.917.7 keV
3.3 keV
26.3
241Am
SiC Pixel DetectorV
bias=200 V
shaping: 6s
Cou
nts
Energy [ keV ]
Room and High Temperature X-ray Spectroscopy
G. Bertuccio et al., “Silicon carbide for high resolution X-ray detectors operating up to 100°C”, Nucl. Instr. Meth. in Physics Res. A 522 (2004) 413
315 eV FWHM = Equivalent noise energy = 797 eV FWHM
Limited by the gate leakage current of the silicon front-end FET
No other detector-grade semiconductor is capable of
operation at high temperatures
2419-10-2004 E.Vittone, IEEE-RTSD, ROME
(MIP) PARTICLE SPECTROSCOPY
Dipartimento di Energetica, Università di Firenze (I) (S.Sciortino)
From CREE
From IKZ ND-NA=8.4·1013 cm-3
Barrier height 1.8 eV
Ideality factor=1.07
Reverse current @ 300 V = 4.4·10-10 A
S+PM trigger
Amptek Acquisition system
90Sr 0.1mCi
S+PM trigger
AmptekAmptek Acquisition system
90Sr 0.1mCi
2519-10-2004 E.Vittone, IEEE-RTSD, ROME
(MIP) PARTICLE SPECTROSCOPY
Pedestal
Number of e/h per m for MIPs = 55
Detector thickness = 40 m
SNR=6
2619-10-2004 E.Vittone, IEEE-RTSD, ROME
ION SPECTROSCOPY
He ion spectra @150 V bias voltageEnergy Loss of He ions in SiC
The electron-hole pair generation energy εSiC SiC has been experimentally determined by comparing the spectral responses of several 4H-SiC Schottky diodes and a Si nuclear detector (εSi=3.62 eV) at room temperature using He ions of different energies.
Energy Loss of He ions in SiC
0 1 2 3 4 8 12 16 200
100
200
300
400
500
600
700
800
Depletion layer width @ 150 V
1.0 MeV He++ 1.5 MeV He++ 2.0 MeV He++ 5.48 MeV He++
Ene
rgy
Loss
(keV
/um
)
Depth (m)
He ion spectra @ 150 V bias voltage
0 200 400 600 800 1000 1200 1400 1600
1000
2000
3000
4000
5000
6000
SiE=a+b*Ch
SiCE=*Ch
Ene
rgy
[keV
]
channel
eV 2.07.7b
SiSiC
The electron-hole pair generation energy SiC in SiC has been experimentally determined by comparing the spectral responses of several 4H-SiC Schottky diodes and a Si nuclear detector (Si=3.62 eV) at room temperature using He ions of different energies.
100 200 500 6000
200
400
600
800
1000
1200 5.48 MeV 2.0 MeV 1.7 MeV 1.5 MeV 1.2 MeV 1.0 MeVC
ount
sChannel
Energy Loss of He ions in SiC
0 1 2 3 4 8 12 16 200
100
200
300
400
500
600
700
800
Depletion layer width @ 150 V
1.0 MeV He++ 1.5 MeV He++ 2.0 MeV He++ 5.48 MeV He++
Ene
rgy
Loss
(keV
/um
)
Depth (m)
He ion spectra @ 150 V bias voltage
0 200 400 600 800 1000 1200 1400 1600
1000
2000
3000
4000
5000
6000
SiE=a+b*Ch
SiCE=*Ch
Ene
rgy
[keV
]
channel
eV 2.07.7b
SiSiC
The electron-hole pair generation energy SiC in SiC has been experimentally determined by comparing the spectral responses of several 4H-SiC Schottky diodes and a Si nuclear detector (Si=3.62 eV) at room temperature using He ions of different energies.
100 200 500 6000
200
400
600
800
1000
1200 5.48 MeV 2.0 MeV 1.7 MeV 1.5 MeV 1.2 MeV 1.0 MeVC
ount
sChannel
Energy Loss of He ions in SiC
0 1 2 3 4 8 12 16 200
100
200
300
400
500
600
700
800
Depletion layer width @ 150 V
1.0 MeV He++ 1.5 MeV He++ 2.0 MeV He++ 5.48 MeV He++
En
erg
y L
oss
(ke
V/u
m)
Depth (m)
He ion spectra @ 150 V bias voltage
0 200 400 600 800 1000 1200 1400 1600
1000
2000
3000
4000
5000
6000
SiE=a+b*Ch
SiCE=*Ch
En
erg
y [
keV
]
channel
eV 2.07.7b
SiSiC
The electron-hole pair generation energy SiC in SiC has been experimentally determined by comparing the spectral responses of several 4H-SiC Schottky diodes and a Si nuclear detector (Si=3.62 eV) at room temperature using He ions of different energies.
100 200 500 6000
200
400
600
800
1000
1200 5.48 MeV 2.0 MeV 1.7 MeV 1.5 MeV 1.2 MeV 1.0 MeVC
ounts
Channel
Energy Loss of He ions in SiC
0 1 2 3 4 8 12 16 200
100
200
300
400
500
600
700
800
Depletion layer width @ 150 V
1.0 MeV He++ 1.5 MeV He++ 2.0 MeV He++ 5.48 MeV He++
En
erg
y L
oss
(ke
V/u
m)
Depth (m)
He ion spectra @ 150 V bias voltage
0 200 400 600 800 1000 1200 1400 1600
1000
2000
3000
4000
5000
6000
SiE=a+b*Ch
SiCE=*Ch
En
erg
y [
keV
]
channel
eV 2.07.7b
SiSiC
The electron-hole pair generation energy SiC in SiC has been experimentally determined by comparing the spectral responses of several 4H-SiC Schottky diodes and a Si nuclear detector (Si=3.62 eV) at room temperature using He ions of different energies.
100 200 500 6000
200
400
600
800
1000
1200 5.48 MeV 2.0 MeV 1.7 MeV 1.5 MeV 1.2 MeV 1.0 MeVC
ounts
Channel
Energy Loss of He ions in SiC
0 1 2 3 4 8 12 16 200
100
200
300
400
500
600
700
800
Depletion layer width @ 150 V
1.0 MeV He++ 1.5 MeV He++ 2.0 MeV He++ 5.48 MeV He++
En
erg
y L
oss
(ke
V/u
m)
Depth (m)
He ion spectra @ 150 V bias voltage
0 200 400 600 800 1000 1200 1400 1600
1000
2000
3000
4000
5000
6000
SiE=a+b*Ch
SiCE=*Ch
En
erg
y [k
eV]
channel
eV 2.07.7b
SiSiC
The electron-hole pair generation energy SiC in SiC has been experimentally determined by comparing the spectral responses of several 4H-SiC Schottky diodes and a Si nuclear detector (Si=3.62 eV) at room temperature using He ions of different energies.
100 200 500 6000
200
400
600
800
1000
1200 5.48 MeV 2.0 MeV 1.7 MeV 1.5 MeV 1.2 MeV 1.0 MeVC
ounts
Channel
Energy Loss of He ions in SiC
0 1 2 3 4 8 12 16 200
100
200
300
400
500
600
700
800
Depletion layer width @ 150 V
1.0 MeV He++ 1.5 MeV He++ 2.0 MeV He++ 5.48 MeV He++
En
erg
y L
oss
(ke
V/u
m)
Depth (m)
He ion spectra @ 150 V bias voltage
0 200 400 600 800 1000 1200 1400 1600
1000
2000
3000
4000
5000
6000
SiE=a+b*Ch
SiCE=*Ch
En
erg
y [k
eV]
channel
eV 2.07.7b
SiSiC
The electron-hole pair generation energy SiC in SiC has been experimentally determined by comparing the spectral responses of several 4H-SiC Schottky diodes and a Si nuclear detector (Si=3.62 eV) at room temperature using He ions of different energies.
100 200 500 6000
200
400
600
800
1000
1200 5.48 MeV 2.0 MeV 1.7 MeV 1.5 MeV 1.2 MeV 1.0 MeVC
ounts
Channel
2719-10-2004 E.Vittone, IEEE-RTSD, ROME
ALPHA PARTICLE SPECTROSCOPY
Plutonium (239P):Americium (241Am):Curium (244Cm):
Peaks: 5.16 MeV (73.1 %); 5.14 MeV (15.0%); 5.10 MeV (11.8 %); others Peaks: 5,49 MeV (85.2 %); 5.44 MeV (12.8 %): 5.39 MeV (1.4 %); othersPeaks: 5.80 MeV (77.4 %); 5.76 MeV (23.0 %); others
15 ± 3 keV = Energy Resolution = 70 ± 15 keV
25 mm2 Si detector
7 mm2 4H-SiC detector
2819-10-2004 E.Vittone, IEEE-RTSD, ROME
1.5 MeVC
CE
2 MeV
0 20 40 60 80 100 120 1400,00,10,20,30,40,50,60,70,80,91,01,1
CCE.OPJ
Applied Bias Voltage (V)
2919-10-2004 E.Vittone, IEEE-RTSD, ROME
0 5 10 15 20 25 30 350
20
40
60
80
100
120
140
160
1800 5 10 15 20 25 30 35
0
20
40
60
80
100
120
140
Ene
rgy
Loss
(ke
V/
m-1)
Depth (m)
2 MeV
1.5 MeV
Bragg.opj
Ap
plied
Bias V
oltag
e (V)
Dep
leti
on
Reg
ion
3019-10-2004 E.Vittone, IEEE-RTSD, ROME
0 5 10 15 20 25 30 350
20
40
60
80
100
120
140
160
1800 5 10 15 20 25 30 35
0
20
40
60
80
100
120
140
Ene
rgy
Loss
(ke
V/
m-1)
Depth (m)
2 MeV
1.5 MeV
Bragg.opj
Ap
plied
Bias V
oltag
e (V)
Dep
leti
on
Reg
ion
FAST DRIFT
COMPLETE COLLECTION DIFFUSION
3119-10-2004 E.Vittone, IEEE-RTSD, ROME
0 5 10 15 20 25 30 350
20
40
60
80
100
120
140
160
180
En
erg
y L
oss (
ke
V/
m-1)
Depth (m)
Drift+Diffusion Model
dxxp
dxdEdx
dxdEQ
d
w
w
0
0 5 10 15 20 25 30 350
20
40
60
80
100
120
140
160
180
Dep
leti
on
reg
ion
@ 2
0 V
En
erg
y L
oss (
ke
V/
m-1)
Depth (m)
0 5 10 15 20 25 30 350
20
40
60
80
100
120
140
160
180
Dep
leti
on
reg
ion
@ 4
0 V
En
erg
y L
oss (
ke
V/
m-1)
Depth (m)
2 MeV protons
0 5 10 15 20 25 30 350
20
40
60
80
100
120
140
160
180
Depletion region @ 140 V
En
erg
y L
oss (
ke
V/
m-1)
Depth (m)
3219-10-2004 E.Vittone, IEEE-RTSD, ROME
1.5 MeV
CC
E
2 MeV
0 20 40 60 80 100 120 1400,00,10,20,30,40,50,60,70,80,91,01,1
CCE.OPJ
Applied Bias Voltage (V)
Lp=(7.0±0.3) m
Dp = 3 cm2/s
p= 160 ns
dxxp
dxdEdx
dxdECCE
d
w
w
0
In virgin samples, L is constant and
p+(x)=sinh[(d-x)/L]/sinh[(d-w)/L]
3319-10-2004 E.Vittone, IEEE-RTSD, ROME
RADIATION
DAMAGE
3419-10-2004 E.Vittone, IEEE-RTSD, ROME
0 50 100 150
He++ 4.14 MeV
REVERSE BIAS (V)
experimental theoretical fit drift only diffusion only
0 50 100 1500
10
20
30
40
50
60
70
80
90
100
CC
E (
%)
He++ 5.48 MeV
REVERSE BIAS (V)
0 20 40 60 80 1000
10
20
30
40
50
60
70
80
90
100
He++ 2.00 MeV
REVERSE BIAS (V)
24 GeV proton irradiation
FLUENCE = 9.37 x 1013 p/cm2
3519-10-2004 E.Vittone, IEEE-RTSD, ROME
0 50 100 150 200 250
20
40
60
80
100
20
40
60
80
100
20
40
60
80
100
0 Mrad
Lp = 9.9 m
p = 329.0 ns
a)
CC
E (
%)
CC
E (
%)
CC
E (
%)
REVERSE BIAS (V)
c)
40 Mrad
Lp = 1.6 m
p = 8.4 ns
2 Mrad
Lp = 5.0 m
p = 84.4 ns
b)
0 50 100 150 200 250
20
40
60
80
100
0 Mrad
Lp = 9.5 m
p = 303.0 ns
a)
CC
E (
%)
CC
E (
%)
CC
E (
%)
REVERSE BIAS (V)
20
40
60
80
100 c)
40 Mrad
Lp = 1.0 m
p = 3.30 ns
20
40
60
80
100
2 Mrad
Lp = 2.0 m
p = 13.5 ns
b)
8.2 MeV electrons -rays from a 60Co source
Ion probe:4.14 MeV alpha particles
3619-10-2004 E.Vittone, IEEE-RTSD, ROME
C/V Alpha spectroscopy
Sample Neff
(cm3)
eV)
n L(m)
Virgin 2.18E15 1.7 1.19 8.57
Proton irradiated1014 p/cm2
1.43E15 1.72 1.18 1.0
Virgin 2.49E15 1.03 1.04 9.5
Electron irradiated2 Mrad
2.69E15 1.06 1.04 2
Electron irradiated20 Mrad
1.67E15 1.13 1.036 1
Virgin 2.49E15 1.03 1.034 9.9
Gamma irradiated20 Mrad
2.28E15 1.03 1.033 5
Gamma irradiated40 Mrad
2.21E15 1.03 1.034 1.6
3719-10-2004 E.Vittone, IEEE-RTSD, ROME
DLTS
Physics Department, University of Bologna, (I)
(A.Cavallini) PHOTOLUMINESCENCE
Material Science Dept., University of Milano Bicocca,
(S.Pizzini)
Virgin:convolution of two donor-acceptor pair recombinations, the one at highest energy related to a transition between a N level and the B level at about Ev+0.35 eV and the one at lowest energy related to a transition between a N level and the B level at about Ev+0.65 eV;
emission at about 1.8 eV: present only in the sample submitted to the highest doses.
Evolution of DLTS spectra of electron irradiated 4H SiC detectors with irradiation fluence. The concentration of traps (S1 – S5) grows linearly with the irradiation dose, while that of S0 is constant.
3819-10-2004 E.Vittone, IEEE-RTSD, ROME
Preliminary neutrons detection Preliminary neutrons detection measurementsmeasurementsTAPIRO: reactor located at ENEA Casaccia Research Centre, Roma.
Epithermal column designed and realized in view of BNCT (Boron Neutron Capture Therapy) treatments (special application: brain tumours)
Total neutron flux @ maximum reactor power (5 kW): 1.15 109 cm2 s-1.
Experimental Physics Dept., University of Torino, (I) (C.Manfredotti, A.Lo Giudice)
3919-10-2004 E.Vittone, IEEE-RTSD, ROME
LiFLiF
66Li(n,Li(n,))33
HH66LiLi
4He
E=2.05 MeV
3H
E=2.73 MeV
SiC detector
DetectorDepletion layer > 30 m
Thickness: 50 m
neutron
Neutron detectorsNeutron detectors
Penetration in SiC: 44HeHe = 4.8 m 33HH=27.4 m
4019-10-2004 E.Vittone, IEEE-RTSD, ROME
7 mm2 electrode
No changes up to a fluence of 1013 neutroni/cm2
2.73 MeV
1.8 mm2 electrode
Experimental Physics Dept., University of Torino, (I) (C.Manfredotti, A.Lo Giudice)
4119-10-2004 E.Vittone, IEEE-RTSD, ROME
CONCLUSIONS
N-type 4H-SiC epitaxial Schottky diodes were manufactured
doping concentration > 5·1013 cm-3
low reverse current for T ≥ 25°C
X-ray detection at high temperature
Beta (MIP) detection (active region thickness = 40 m, SNR=6)
Ion spectroscopy (FWHM=70keV, A=7 mm2)
Complete charge collection at the depletion layer in strongly irradiated samples.
Neutron detection