19-10-2004 1e.vittone, ieee-rtsd, rome silicon carbide for alpha, beta, proton and soft x-ray high...

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


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


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”


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


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


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


DIODE MANUFACTURE


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


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)


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


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.


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”


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


[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


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


Amplifier

Electrode

X

Y

Sample

Vbias


Amplifier

Electrode

X

Y

IBICCIon Beam Induced Charge Collection

Microscopy

Experimental Physics Dept., University of Torino, (I)


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


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)


Optical microscope image

XBIC map of two electrodes XBIC profile


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


DETECTOR PERFORMANCES


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


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




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 ]


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 ]


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


(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


(MIP) PARTICLE SPECTROSCOPY

Pedestal

Number of e/h per m for MIPs = 55

Detector thickness = 40 m

SNR=6


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


0 1 2 3 4 8 12 16 200

100

200

300

400

500

600

700

800



Ene

rgy

Loss

(keV

/um

)

Depth (m)


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


100 200 500 6000

200

400

600

800

1000


ount

sChannel


0 1 2 3 4 8 12 16 200

100

200

300

400

500

600

700

800



En

erg

y L

oss

(ke

V/u

m)

Depth (m)


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


100 200 500 6000

200

400

600

800

1000


ounts

Channel


0 1 2 3 4 8 12 16 200

100

200

300

400

500

600

700

800



En

erg

y L

oss

(ke

V/u

m)

Depth (m)


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


100 200 500 6000

200

400

600

800

1000


ounts

Channel


0 1 2 3 4 8 12 16 200

100

200

300

400

500

600

700

800



En

erg

y L

oss

(ke

V/u

m)

Depth (m)


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


100 200 500 6000

200

400

600

800

1000


ounts

Channel


0 1 2 3 4 8 12 16 200

100

200

300

400

500

600

700

800



En

erg

y L

oss

(ke

V/u

m)

Depth (m)


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


100 200 500 6000

200

400

600

800

1000


ounts

Channel


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


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)


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


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


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)


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]


RADIATION

DAMAGE


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


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


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


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.


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)


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


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)


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

19-10-2004 1e.vittone, ieee-rtsd, rome silicon carbide for alpha, beta, proton and soft x-ray high...

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