Veljko Grilj Ru đ er Bošković Institute, Zagreb, Croatia Silicon Detector Workshop Split, Croatia, 8-10 October 2012

DETECTOR TESTING FACILITY AT RBI(IBIC (Ion Beam Induced Charge) EXPERIMENT)

Veljko Grilj

Ruđer Bošković Institute, Zagreb, Croatia

Silicon Detector WorkshopSplit, Croatia, 8-10 October 2012

1. ACCELERATORS 1.0 MV HVE

Tandetron accelerator

6.0 MV EN Tandem Van de Graaff accelerator

IAEA beam line

TOF ERDA

PIXE/RBS

Dual-beam

irradiation

Ion microprobe

Nuclear reactions

In-air PIXE

PIXE crystal spectromet

er

Det.test

.IBIC

12

1.1. New detector testing beam line

1. Beam deflector and/or scanner

2. Pre-chamber with beam degrader/diffuser

3. Final chamber with beam in air capability

1.2. Nuclear microprobe

XY

protonbeam

scangenerator

XY

quadrupole doubletfocusing lens

sampleobject slits

IBIC signal

IBIC - chargecollection efficiency

images

IONS- p, , Li, C, O,..

RANGE - 2 to 200 m

ION RATE- currents 0 - 106 p/s

ION POSITION- focusing and scanning

500 10001E-6

1E-5

1E-4

1E-3

0,01

0,1

1

10

100

1000

10000

100000

Num

ber of

cha

rge

pairs

(io

n*nm

)-1

Depth (nm)

protons

CSi

Cu I

Eions = 1 MeV/amuMIPs

Silicon I 127 Si 28 C 12 He 4 H 1

Range(µm)E=1 MeV

0.37 1.13 1.6 3.5 16.3

Range (µm)E=10 MeV

3.7 4.8 9.5 69.7 709

proton

He12C

28Si127I

1.3. Available ion beams

Accel. voltages 0.1 to 6.0 MVNegative Ion sources:- Duoplasmatron- RF He- Sputtering

2. ION BEAM INDUCED CHARGE - theory

V

Q

V

Vout

Ouput signal Vout

Deposited energy

Principles of radiation detection techniques

Vout = F (deposited energy, free carrier transport)

Nuclear spectroscopy Well known

Free charge genetration and

transport


V

Q

V

Vout

Ouput signal Vout

Deposited energy

Principles of IBIC

Vout = F (deposited energy, free carrier transport)

Free charge genetration and

transport

Well known Material characterization


2

2

2

220

20

24

1ln2

ln4

c

v

c

v

I

vmNZ

vm

ze

dx

dE

Bethe formula:

a) Energy deposition by ions

Principles of IBIC

b) Creation of e-h pairs

6/ 10

eV

MeVEN

eh

dephe


c) Free charge carrier transport → charge induced at electodes

Principles of IBIC

.

))((

constVii

jV

trEvqi

Gunn’s theorem:

-2 0 2 4 6 8 10 12 14

0.000

0.025

0.050

0.075

0.0

0.2

0.4

0.6

0.8

1.0

I

Time

Q

V

Q

V

Vout

d

T=0

vd

vq)t(I

year 1964



Principles of IBIC

.

))((

constVii

jV

trEvqi

Gunn’s theorem:

V

Q

V

Vout

d

-2 0 2 4 6 8 10 12 14

0.000

0.025

0.050

0.075

0.0

0.2

0.4

0.6

0.8

1.0

I

Time

Q

T=1

d

vq)t(I



Principles of IBIC

.

))((

constVii

jV

trEvqi

Gunn’s theorem:

-2 0 2 4 6 8 10 12 14

0.000

0.025

0.050

0.075

0.0

0.2

0.4

0.6

0.8

1.0

I

Time

Q

V

Q

V

Vout

d

T=2

d

vq)t(I



Principles of IBIC

.

))((

constVii

jV

trEvqi

Gunn’s theorem:

-2 0 2 4 6 8 10 12 14

0.000

0.025

0.050

0.075

0.0

0.2

0.4

0.6

0.8

1.0

I

Time

Q

V

Q

V

Vout

d

T=3

d

vq)t(I



Principles of IBIC

.

))((

constVii

jV

trEvqi

Gunn’s theorem:

V

Q

V

Vout

d

-2 0 2 4 6 8 10 12 14

0.000

0.025

0.050

0.075

0.0

0.2

0.4

0.6

0.8

1.0

I

Time

Q

T=4

d

vq)t(I



Principles of IBIC

.

))((

constVii

jV

trEvqi

Gunn’s theorem:

-2 0 2 4 6 8 10 12 14

0.000

0.025

0.050

0.075

0.0

0.2

0.4

0.6

0.8

1.0

I

Time

Q

V

Q

V

Vout

d

T=5

d

vq)t(I



Principles of IBIC

.

))((

constVii

jV

trEvqi

Gunn’s theorem:

-2 0 2 4 6 8 10 12 14

0.000

0.025

0.050

0.075

0.0

0.2

0.4

0.6

0.8

1.0

I

Time

Q

V

Q

V

Vout

d

T=6

d

vq)t(I



Principles of IBIC

.

))((

constVii

jV

trEvqi

Gunn’s theorem:

-2 0 2 4 6 8 10 12 14

0.000

0.025

0.050

0.075

0.0

0.2

0.4

0.6

0.8

1.0

I

Time

Q

V

Q

V

Vout

d

T=7

d

vq)t(I



Principles of IBIC

.

))((

constVii

jV

trEvqi

Gunn’s theorem:

-2 0 2 4 6 8 10 12 14

0.000

0.025

0.050

0.075

0.0

0.2

0.4

0.6

0.8

1.0

I

Time

Q

V

Q

V

Vout

d

T=8

d

vq)t(I



Principles of IBIC

.

))((

constVii

jV

trEvqi

Gunn’s theorem:

-2 0 2 4 6 8 10 12 14

0.000

0.025

0.050

0.075

0.0

0.2

0.4

0.6

0.8

1.0

I

Time

Q

V

Q

V

Vout

d

T=9

d

vq)t(I



Principles of IBIC

.

))((

constVii

jV

trEvqi

Gunn’s theorem:

-2 0 2 4 6 8 10 12 14

0.000

0.025

0.050

0.075

0.0

0.2

0.4

0.6

0.8

1.0

I

Time

Q

V

Q

V

Vout

d

T=10

d

vq)t(I



Principles of IBIC

.

))((

constVii

jV

trEvqi

Gunn’s theorem:

-2 0 2 4 6 8 10 12 14

0.000

0.025

0.050

0.075

0.0

0.2

0.4

0.6

0.8

1.0

I

Time

Q

V

Q

V

Vout

d

T=11


Impact of defects on charge carriers mobility:

Principles of IBIC

-2 0 2 4 6 8 10 12 14 16

0.000

0.025

0.050

0.075

0.0

0.2

0.4

0.6

0.8

1.0

I

Time

Q

-2 0 2 4 6 8 10 12 14

0.000

0.025

0.050

0.075

0.0

0.2

0.4

0.6

0.8

1.0

I

Time

Q

d

vqI

qQtot

qQtot

t

d

vqI exp

created

induced

Q

QCCE - physical opservable:


Principles of IBIC

startifinali

induced VVqQ

- direct implication from Gunn’s theorem:

.

))((

constVii

jV

trEvqi

- consequences:

electronsholes

ion beam

CCE 100%

a)

b)

- V0 - V0

-V 0

he


Advantages of using focused ions:- spatial resolution- wide spread of ion ranges

Principles of IBIC

20

mm

20 mm

Electrons10 keV

Electrons40 keV2 MeV H+ in Si 3 MeV H+ in Si

4 MeV H+ in Si

2 mm

4 mm

6 mm

47 m

m

90 m

m 147

mm

2. ION BEAM INDUCED CHARGE

PIN diode

Samples


CVDdiamond

CdInGaSesolar cell

Si DSSD(16x16 strips)

Ion beam

Samples

Laura Grassi, W

ednesday,

16:00h


100 m

Geometries

3. IBIC EXAMPLES

- by proper selection of ion type and energy, CCE (charge collection efficiency) at different sample depths can be imaged.

4.5 MeV Lirange 6μm

3 MeV protonsrange 90 μm

Si Schotky diode

proton

He12C

28Si127I

surface

bulk

Frontal IBIC

3. IBIC EXAMPLES

4.5 MeV Li7 ions (range in Si 8.5 m)

7.875 O16 ions(range in Si 4.5 m)

8.25.4

0

5.4

0

m

ionsLi

m

ionsO

dxdxdE

dxdxdE

Li image - O image / 2.8IBIC between 4.5 and 8.5 m

Frontal IBIC – depth profiling

Si Schotky diode

3. IBIC EXAMPLES

Frontal IBIC – drift & diffusion

d

W p

W

neutraldepletion dxL

Wx

dx

dEdx

dx

dEQQQ exp

0

drift diffusion

E ≠ 0

E = 0

minority carrier diffusion length

4H-SiC diode

3. IBIC EXAMPLES

d

W p

W


Wx

dx

dEdx

dx

dEQQQ exp

0

drift diffusion

E ≠ 0

E = 0


4H-SiC diode

3. IBIC EXAMPLES

d

W p

W


Wx

dx

dEdx

dx

dEQQQ exp

0

drift diffusion

E ≠ 0

E = 0


4H-SiC diode

3. IBIC EXAMPLES

d

W p

W


Wx

dx

dEdx

dx

dEQQQ exp

0

drift diffusion

E ≠ 0

- direct measurement of diffusion length

Lp = (9.0±0.3) μm


4H-SiC diode

3. IBIC EXAMPLES

Frontal IBIC – μτ mapping

E

d

d

ECCE

eh

eh

/

/ exp1

- from Gunn’s theorem with assumptions of full depletion, constant electric field and generation near one electrode:

Vcmave /101 23,

Vcmavh /104 25,

electrons holes

Hecht equation

CdZnTe- sample thickness > 2 mm

- IBIC with 2 MeV p+, range < 30 μm

M. Veale et al., IEEE TNS, 2008

Si power diode

E = 0

pn junction

E < 0

ion beam

0 zdz

CCE (z<zd) ≈ 1

CCE (z>zd) = exp(-(z-zd)/Lp,n)

hole or electrondiffusion length

3. IBIC EXAMPLES

Lateral IBIC – drift and diffusion

3 MeV proton beam

X-Y scanning

Cooling-heating

Bias Preamplifier Amplifier

ADC

Digital oscilloscope

DSO

TRIBIC

DAQ

IBIC MAPS

CdZnTe

Au-contacts

3. IBIC EXAMPLES

Temperature dependent lateral IBIC

CdZnTe

- temperature range 166-329 K

(mt)e=(1.4)*10-3 cm2/V(mt)h=1*10-5 cm2/V

(mt)e=(1.4)*10-3 cm2/V(mt)h=1*10-5 cm2/V

IBIC line scan (anode to cathode)for CCE=100%

3. IBIC EXAMPLES

Temperature dependent lateral IBIC

CdZnTe

3. IBIC EXAMPLES

Radiation hardness tests

- For 100% ion impact detection efficiency, IBIC

can be used to monitor irradiation fluence

- Irradiation of arbitrary shapes

- On-line monitoring of CCE degradation

Ion beam induced damage:

50 Li7 m-2 = 5×109 cm-2

6 Li7 m-2 = 6×108 cm-2

(4 events per pixel)

IBIC on-line monitoring:

Irradiation pattern (3 x3 quadrants, 50 x 50 pixels, 100 x 100 m2 each, 20 m gaps, tirrad = 5 min. – 3 h )

3. IBIC EXAMPLES

Radiation hardness tests

- damage done with He, Li, O & Cl ions of similar range

Si diode

3. IBIC EXAMPLES

Radiation hardness tests Modeling of CCE:- doping profiles & el. field (CV)- drift velocity profiles (el. field)- hole contribution negligible- vacancy profile (SRIM)- predominantly divacancies (DLTS)- dE/dx from (SRIM)- electron lifetime:

k = 0.88 *10-15

k = 0.18 !!18% of radiation induced defects leads to stable

divacancies !

heheKCCE ,*

,*1

hehek ,, effective fluence

Si diode

4. ION INDUCED DLTS

Question: how to calculate the energy levels of produced traps?

Answer: DLTS, but what if.....a) number of traps is very very large? b) I want good spatial resolution? c) my sample is diamod?

Radiation produces lattice defects el. active traps, CCE<100%

4. ION INDUCED DLTS

Question: how to calculate the energy levels of produced traps?

Answer: DLTS, but what if.....a) number of traps is very very large? b) I want good spatial resolution? c) my sample is diamod?

Ion Induced

DLTSSteps:- IBIC with MeV ions, charge carriers will fill traps - record cumulative collected charge in time using charge sensitive preamp and digital scope at different temperatures- choose rate windows like in conventional DLTS- plot Q(t2)-Q(t1) vs. T

- make Arrhenius analysis and get activation energy of the defect

Radiation produces lattice defects el. active traps, CCE<100%

4. ION INDUCED DLTS 6H-SiC diode

- irradiation with 1 MeV electrons, 215101 cm el. active traps, CCE<100%

- IBIC with 5.486 MeV alphas

cumulative collected charge 250K<T<320 K

Q(t2)-Q(t1) vs. T

Estimated activation energy:IIDLTS DLTS

0.50±0.05 eV 0.53±0.07 eV

N. Iwamoto et al., IEEE TNS, 2011

5. TIME RESOLVED IBIC - TRIBIC

C. Canali, E. Gatti, S.F. Koslov, P.F. Manfredi, C. Manfredotti, F. Nava, A. QuiriniNucl. Instr. Meth. 160 (1979) 73-77

t

d

vqI exp

ns15

(transient current technique, TCT)- use of current sensitive amplifier instead of charge

sensitive- high frequency oscilloscope, - novel technique ???

400 μm thick natural diamond


- 2 GHz, 40 dB, 200ps rise time amplifier (CIVIDEC)- broad-band 3GHz scope (LeCroy)

TCT on scCVD diamond at low temperatures

H. Jansen (CERN), CARAT Workshop, GSI, 2011

Lower fields are required to reach saturation velocity at low tempertures


Saturation velocity


Plasma effects


Plasma effects

Significantely higher charge trapping at low temperatures !!


Charge trapping/detrapping


Detrapping (~ 10 ns)


Charge trapping/detrapping



Position sensitivity- scCVD diamond, 500 μm thick- lateral scan with 4.5 MEV p- (μτ)e< (μτ)h

- 6 GHz, 15dB preamp (Minicircuits)- 5 GHz, 10 GS/s scope (LeCroy)

0 500μm

Achievable resolution ≈ 10 μm

500 μm thick scCVD diamond

Thank you for attention!

Documents

Veljko Grilj Ru đ er Bošković Institute, Zagreb, Croatia Silicon Detector Workshop Split, Croatia, 8-10 October 2012