Eduardo del Castillo Sanchez , Manuel Fahrer , Michael Moll, Nicola Pacifico

Study on 50 75 and 150Study on 50 75 and 150m m thick thick p-type Epitaxial silicon pad p-type Epitaxial silicon pad detectors irradiated with detectors irradiated with protons and neutronsprotons and neutrons

Eduardo del Castillo Sanchez, Manuel Fahrer, Michael Moll, Nicola Pacifico

Pad detector Characterization16th RD50 Workshop – Barcelona 31st May - 2nd June 2010

1

16th RD50 Workshop on Radiation Hard Semiconductor Devices For Very High Luminosity Colliders

OutlineOutlineStudied samples and irradiationsCV/IV measurements

◦ Tools◦ Results

TCT measurements◦ Tools◦ Results

CCE measurements◦ Tools◦ Results

Conclusions

216th RD50 workshop, Barcelona. 31st May - 2nd June

2010 Eduardo del Castillo

Studied samples and Studied samples and irradiationsirradiations

The material used in this study was produced by ITME

Epitaxial layers are grown on a highly B doped 0.02 cm CZ substrate

24GeV/c proton irradiation (CERN PS), eq= 8 x 1011 – 5 x 1015 cm-2

Some CNM-22 samples irradiated with reactor neutrons (TRIGA reactor, Ljubljana)

eq= 7 x 1012 – 3 x 1015 cm-2

Hardness factor of 0.62 used to convert 24 GeV/c protons to equivalent fluences

All samples were annealed to 4min 80oC

3

Producer d [um]

[cm]

Producer(sensor)

Device labels

Size [mm2]

Vdep [V]

|Neff| [1012cm-3]

ITME 50 220 CiS W3/W4/W5

2. 5 x 2.5 113.1 ± 2.1

59.5 ± 1.11

ITME 75 350 CiS W9/W10 2.5 x 2.5 187.5 ± 12.5

43.88 ± 2.93

ITME 150 1000 CNM CNM22 5 x 5 211.4 ± 21.3

12.37 ± 1.25

16th RD50 workshop, Barcelona. 31st May - 2nd June 2010 Eduardo del Castillo

CV/IV measurementsCV/IV measurements

4

• Sample connections in two ways◦ Using the probe station

◦ Through SMA connectors on PCB boards over which samples can be mounted

• CV / IV Switch

• Temperature control ◦ Sensor close to sample under test (e)

◦ Monitored by user in a LCD screen (f)

g

• CV measurement◦ Keithley 237 used as Voltage Source

(b)

◦ Agilent 4263B LCR meter operating Agilent 4263B LCR meter operating at 10 KHz in parallel mode (a)at 10 KHz in parallel mode (a)

• IV measurement◦ Keithley 2410 source meter (c)

◦ Keithley 485 current meter were used (g)

• In all diodes, guard ring is connected to ground and biasing is applied from the backIn all diodes, guard ring is connected to ground and biasing is applied from the back

g

• LabView software for interfacing the setup and postprocessing the data


ToolsTools

• Measurements at room temperatureMeasurements at room temperature

CV/IV measurements CV/IV measurements

5

eqcc

eff geNN eq 0

-5 0 5 10 15 20

x 1014

0

10

20

30

40

50

Equivalent Fluence [cm-2]

|Nef

f| [1

012cm

-3]

Curves extracted from CV measurements

50 m. protons. gc = (14.65 0.72) x 10-3 [cm-1]

75 m. protons. gc = (16.29 0.38) x 10-3 [cm-1]

150 m. protons. gc = (9.98 1.41) x 10-3 [cm-1]

150 m. neutrons. gc = (8.07 1.48) x 10-3 [cm-1]


Results. NResults. Neffeff vs fluence vs fluence

Comparing with data in n-type from Hamburg group

[Data measured by K.Kaska and presented in the 15th RD50 Workshop]

-5 0 5 10 15 20

x 1014

0

10

20

30

40

50


|Nef

f| [1

012cm

-3]

Curve extracted from IV measurements

50 m. protons. gc = (10.23 0.53) x 10-3 [cm-1]

75 m. protons. gc = (13.71 0.26) x 10-3 [cm-1]

150 m. protons. gc = (6.13 1.71) x 10-3 [cm-1]

150 m. neutrons. gc = (9.94 1.06) x 10-3 [cm-1]

Fitting model

Thickness [m] 50 75 150

gc (n-type) [10-

3cm-1]-

23-

12-6

gc (p-type) [10-

3cm-1]15 16 10[Data extracted from “ Microscopic study of proton irradiated

epitaxial Silicon Detectors “ talk, in the 15th RD50 Workshop]

TCT measurementsTCT measurements

6

• Laser wavelength 660 nm (ps pulses)• Cooled with silicon oil (down to -25

o C)

• Dry air atmosphere (humidity less than 5%)• Laser can be scanned over DUT with linear motor

stage and X-Y screws• Laser illumination only in the front of the sample Laser illumination only in the front of the sample

due to the thickness of the CZ substrate due to the thickness of the CZ substrate • Sample boards (support PCB)• Diodes are biased from the frontDiodes are biased from the front• Measurements at 5Measurements at 5oo

C C


ToolsToolsSr 90

Source

PCB support

PM

laser focuser cooling plate

laser & source movable against support plate: DUT

d

5 10 15 20 25 30

-0.2

-0.15

-0.1

-0.05

0

t [ns]

I [V

/50

]

20 Volts 40 Volts 60 Volts 80 Volts100 Volts120 Volts140 Volts160 Volts180 Volts200 Volts220 Volts240 Volts

0 5 10 15 20 25 30

-0.2

-0.15

-0.1

-0.05

0

t [ns]

I [V

/50

]

20 Volts 50 Volts 80 Volts110 Volts140 Volts170 Volts200 Volts230 Volts260 Volts290 Volts320 Volts350 Volts

0 10 20 30 40

-0.15

-0.1

-0.05

0

t [ns]

I [V

/50

]

Vdep = VoltsVdep = Volts

35 Volts 50 Volts 65 Volts 80 Volts 95 Volts110 Volts125 Volts140 Volts155 Volts170 Volts185 Volts200 Volts

0 10 20 30 40

-0.12

-0.1

-0.08

-0.06

-0.04

-0.02

0

t [ns]

I [V

/50

]

16 Volts 31 Volts 46 Volts 61 Volts 76 Volts 91 Volts106 Volts121 Volts136 Volts

TCT measurements TCT measurements

7


Results. Current pulses (not Results. Current pulses (not corrected)corrected)

d = 50 mVdep = 12.5 V24 GeV/c protonseq = 5.02 x 1014 cm-2



d = 150 mVdep = 99.36 VReactor neutronseq = 3 x 1014 cm-2


8

• For For proton-irradiationproton-irradiation we have type inversion in the bulk we have type inversion in the bulk

• Now is possible the estimation of the trapping times for holes Now is possible the estimation of the trapping times for holes with the charge with the charge correction method [Gregor Kramberger´s doctoral thesis]correction method [Gregor Kramberger´s doctoral thesis]

• The amount of drifting charge decreases with time due to trapping asThe amount of drifting charge decreases with time due to trapping as


Results. Trapping time Results. Trapping time estimationestimation

,

, ,( ) (0) effe h

t

e h e hN t N e

• Effective trapping time can be got from the current integral at voltages Effective trapping time can be got from the current integral at voltages above full depletionabove full depletion

• Correcting measured current with an exponential can compensate for Correcting measured current with an exponential can compensate for trappingtrapping

• The integral of IThe integral of Icc over time is equal for all voltages above depletion over time is equal for all voltages above depletion

0

( ) ( ) tr

t t

c mI t I t e


9


Results. Current pulses Results. Current pulses correctedcorrected

(d = 50 (d = 50 m)m)

4 6 8 10 12 14

-0.15

-0.1

-0.05

0

Time [ns]

I [V

/50

]

eq

= 2.10 x 1014 cm-2 (protons). = 5.8ns

26 Volts 36 Volts 46 Volts 56 Volts 66 Volts 76 Volts 86 Volts 96 Volts106 Volts

1 1.5 2 2.5 3

-0.25

-0.2

-0.15

-0.1

-0.05

0

Time [ns]

I [V

/50

]

eq

= 5.02 x 1014 cm-2 (protons). = 3.08ns

41 Volts 51 Volts 61 Volts 71 Volts 81 Volts 91 Volts101 Volts

5 10 15 20 25-0.1

-0.08

-0.06

-0.04

-0.02

0

Time [ns]

I [V

/50

]

eq= 1.10 x 1014 cm-2 (protons). = 14.82ns

23 Volts 43 Volts 63 Volts 83 Volts103 Volts123 Volts143 Volts163 Volts183 Volts203 Volts

TCT measurementsTCT measurements

10



(d = 75 (d = 75 m)m)

0 5 10 15-0.12

-0.1

-0.08

-0.06

-0.04

-0.02

0

0.02

Time [ns]

I [V

/50

]

eq= 2.69 x 1013 cm-2 (protons). = 23ns

75 Volts 80 Volts 85 Volts 90 Volts 95 Volts100 Volts105 Volts

4 6 8 10 12 14-0.2

-0.15

-0.1

-0.05

0

Time [ns]

I [V

/50

]

eq

= 2.10 x 1014 cm-2 (protons). = 6.17ns

45 Volts50 Volts55 Volts60 Volts65 Volts70 Volts75 Volts80 Volts85 Volts

4 4.5 5 5.5 6 6.5

-0.35

-0.3

-0.25

-0.2

-0.15

-0.1

-0.05

0

Time [ns]

I [V

/50

]

eq

= 5.02 x 1014 cm-2 (protons). = 3.83ns

80 Volts 85 Volts 90 Volts 95 Volts100 Volts105 Volts110 Volts115 Volts


11

2 4 6 8 10 12 14 16 18

-0.12

-0.1

-0.08

-0.06

-0.04

-0.02

0

Time [ns]

I [V

/50

]

eq

= 3.14 x 1013 cm-2 (protons). = 45ns




(d = 150 (d = 150 m)m)

2 4 6 8 10 12 14 16-0.35

-0.3

-0.25

-0.2

-0.15

-0.1

-0.05

0

Time [ns]

I [V

/50

]

eq

= 2.75 x 1014 cm-2 (protons). = 6.85ns

100 Volts110 Volts120 Volts130 Volts140 Volts150 Volts

2 4 6 8 10 12 14 16

-0.5

-0.4

-0.3

-0.2

-0.1

0

Time [ns]

I [V

/50

]

eq

= 5.09 x 1014 cm-2 (protons). = 4.88ns

180 Volts190 Volts200 Volts210 Volts220 Volts230 Volts240 Volts250 Volts


12



(d = 150 (d = 150 m)m)

0 5 10 15-0.2

-0.18

-0.16

-0.14

-0.12

-0.1

-0.08

-0.06

-0.04

-0.02

0

Time [ns]

I [V

/50

]

eq= 3 x 1013 cm-2 (neutrons). = 42.8ns


0 5 10 15 20-0.25

-0.2

-0.15

-0.1

-0.05

0

Time [ns]

I [V

/50

]

eq

= 1014 cm-2 (neutrons). = 18.56ns


2 4 6 8 10 12

-0.4

-0.3

-0.2

-0.1

0

Time [ns]

I [V

/50

]

eq

= 3 x 1014 cm-2 (neutrons). = 5.59ns



13

• We only take those samples until We only take those samples until eqeq = 3 x 10 = 3 x 101414 cm cm-2-2

eq

1

• Fitting model : Fitting model :

• For proton irradiation : 50m= (7.76 ± 1.55) x 10-16 [cm2ns-

1] 150m= (7.85 ± 1.93) x 10-16 [cm2ns-

1] 150m= (5.33 ± 0.36) x 10-16 [cm2ns-

1] 16th RD50 workshop, Barcelona. 31st May - 2nd June


Results. Hole trapping time Results. Hole trapping time estimationestimation

0 0.5 1 1.5 2

x 1015

0

0.5

1

1.5


1/

[ns-1

]

Trapping time estimation

d = 50 m. Proton-irradiatedd = 75 m. Proton-irradiatedd = 150 m. Proton-irradiatedd = 150 m. Neutron-irradiated

0 0.5 1 1.5 2 2.5 3

x 1014

0

0.05

0.1

0.15

0.2


1/

[ns-1

]

Trapping time estimation

d = 50 m. Proton-irradiatedd = 75 m. Proton-irradiatedd = 150 m. Proton-irradiatedd = 150 m. Neutron-irradiated

• For neutron irradiation : 150m= (5.92 ± 0.23) x 10-16 [cm2ns-1]

CCE measurementsCCE measurements

14

Charge amplification◦ Sensitivity of 0.75 V/pF

Shaping and base line stabilization◦ Rise time of 1us and fall time of 0.85us

◦ Adjustable Gain between 40 and 100

ADC sampling◦ 12 bit ADC in the range of ±5 V

◦ Preamplifier before digitising for higher or lower ranges

Radiactive source Sr 90 Gain of 243 eGain of 243 e--/mV at -20 /mV at -20 oo

CC Biasing from the back and guard ring to Biasing from the back and guard ring to

groundground

• Collimation and Scintillation◦ W/Cu 72/18 alloy collimator with aperture width 0.6

mm2

◦ Plastic scintillator 3 mm wide and long at 9.5 mm under the collimator

◦ Scintillator coupled to a photomultiplier through a long light guide

• X Y and Z screws to adjust collimator and scintillator position

• Temperature control◦ Air temperature block on a Peltier cooler◦ Two thermistors upstream and downstream in the

airflow along the sample◦ Sensirion SHT75 sensor for temperature and

humidity in the air temperature block 16th RD50 workshop, Barcelona. 31st May - 2nd June 2010 Eduardo del Castillo

ToolsTools

Fred HartjesNIKHEF


15

0 5000 10000 150000

100

200

300

400

500

Number of electrons

Num

ber

of c

ount

s

d = 50 m, proton-irradiated. eq

= 2.10 x 1014cm-2

Bias Voltage = 200 VPedestal = 2.37 mVNoise = 623 e-

MPV = 3.039 e-

= 2538 e-

HistogramFitting

0 5000 10000 150000

100

200

300

400

Number of electrons

Num

ber

of c

ount

s


= 2.10 x 1014cm-2

Bias Voltage = 200 VPedestal = 2.35 mV Noise = 414 e- MPV = 5446 e- = 3829 e-

HistogramFitting

-0.5 0 0.5 1 1.5 2 2.5 3

x 104

0

50

100

150

200

250

Number of electrons

Num

ber

of c

ount

s


= 2.75 x 1014cm-2

Bias Voltage = 200 VPedestal = 2.37 mV Noise = 623.57 e- MPV = 3.039.88 e- = 2538.1 e-

Bias Voltage = 200 VPedestal = 2.37 mV Noise = 623.57 e- MPV = 3.039.88 e- = 2538.1 e-


HistogramFitting

-0.5 0 0.5 1 1.5 2 2.5 3

x 104

0

50

100

150

200

250

Number of electrons

Num

ber

of c

ount

s

d = 150 m, neutron-irradiated. eq

= 1014cm-2


HistogramFitting


Results. HistogramsResults. Histograms




Results. Charge collected Results. Charge collected curvescurves

0 50 100 150 2000

500

1000

1500

2000

2500

3000

3500

Voltage [V]

Col

lect

ed C

harg

e [e

- ]d = 50m. PROTON IRRADIATED.

eq

= 2.69 x 10 13 cm-2

eq

= 2.10 x 10 14 cm-2

eq

= 5.02 x 10 14 cm-2

eq

= 1.79 x 10 15 cm-2

0 50 100 150 200 250 300-1000

0

1000

2000

3000

4000

5000

6000

Voltage [V]

Col

lect

ed C

harg

e [e

- ]

d = 75m. PROTON IRRADIATED.

eq

= 2.69 x 1013 cm-2

eq

= 2.10 x 1014 cm-2

eq

= 5.02 x 1014 cm-2

eq

= 1.79 x 1015 cm-2

0 100 200 300 4000

2000

4000

6000

8000

10000

12000

14000

Voltage [V]

Col

lect

ed C

harg

e [e

- ]

d = 150m. PROTON IRRADIATED.

Ref sample

eq

= 3.14 x 1013 cm-2

eq

= 2.75 x 1014 cm-2

eq

= 5.09 x 1015 cm-2

0 50 100 150 200 250 300 3500

2000

4000

6000

8000

10000

12000

14000

Voltage [V]

Col

lect

ed C

harg

e [e

- ]

d = 150m. NEUTRON IRRADIATED.

Ref sample

eq = 3 x 1013 cm-2

eq

= 1 x 1014 cm-2

eq

= 3 x 1014 cm-2

eq

= 1 x 1015 cm-2

17

• We can see a not expected behavior in the curve for We can see a not expected behavior in the curve for thickness 75 thickness 75 mm

• Coherence among the different geometries at low Coherence among the different geometries at low fluences. fluences.

• For 150 For 150 m, we can see a drop in CCE for n-type in m, we can see a drop in CCE for n-type in comparison with comparison with p-type p-type



Results. ComparisonResults. Comparison

0 0.5 1 1.5 2 2.5

x 1015

2000

4000

6000

8000

10000

12000

Equivalent fluence [cm-2]

Char

ge co

llecte

d [e

- ]Charge collected versus fluence when V

bias= 200 V

d = 50 m.p-type. Proton-irradiatedd = 75 m.p-type. Proton-irradiatedd = 150 m.p-type. Proton-irradiatedd = 150 m.p-type. Neutron-irradiatedd = 150 m.n-type. Proton-irradiatedd = 150 m.n-type. Neutron-irradiated

0 2 4 6 8 10 12 14 16 18

x 1014

0.4

0.6

0.8

1

1.2

1.4

Equivalent fluence [cm-2]

Charg

e colle

cted n

ormaliz

ed

Charge collected versus fluence when Vbias

= 200 V

d = 50 m.p-type. Proton-irradiatedd = 75 m.p-type. Proton-irradiatedd = 150 m.p-type. Proton-irradiatedd = 150 m.p-type. Neutron-irradiatedd = 150 m.n-type. Proton-irradiatedd = 150 m.n-type. Neutron-irradiated

[K. Kaska,”Study on 150 um thick n- and p-type epitaxial silicon sensors irradiated with 24GeV/c protons and 1 MeV neutrons” Nucl. Instr. and Meth. A 612 (2010) 482-487]

ConclusionsConclusions CV/IV, TCT and CCE measurements has been performed over a set of p-

type epitaxial diodes of thicknesses 50, 75 and 150 m irradiated with protons and neutrons

It was observed that the variation of the dependence with fluence of Neff , as function of thickness, is slighter in p-type than in n-type detectors

In p-type pad detectors, space charge sign inversion from negative to positive takes place after proton irradiation but not after neutron irradiation

Hole trapping time estimation was performed for all the thicknesses, getting values for 50 and 75 um proton-irradiated devices, in agreement with [1], as well as for 150 um neutron-irradiated.

For 150 um, the charge collected in p-type detectors, for low fluences, doesn´t drop with fluence so fast than for n-type.



[1] J. Lange,” Charge collection studies of proton-irradiated n- and p-type epitaxial silicon detectors” Nucl. Instr. and Meth. A (2010)

END

19

Eduardo del Castillo Sanchez , Manuel Fahrer , Michael Moll, Nicola Pacifico

Documents

data16th rd50 workshop

o c16th rd50 workshop

93itme1501000cnmcnm225

castillocviv measurements

castillotct measurements

castillo results

castillostudied samples

castillo sanchez