comparison of radiation hardness of p-in-n, n-in-n …...giulio pellegrini cern-rd50 conclusions and...

ComparisonComparison of of RRadiationadiation HHardnessardness of Pof P--inin--N, N, NN--inin--N and NN and N--inin--P Silicon P Silicon PPad ad DDetectors etectors

G.Pellegrini, M.Lozano, F.Campabadal, C.Fleta, C.Loderer, M.Ullan

bCentro Nacional de Microelectronica, Barcelona, 08193, Spain

P.Allport, G.CasseaOliver Lodge Laboratory, The University of Liverpool, UK

CERN-RD50Giulio Pellegrini

OutlineOutline

•Introduction

•Fabrication technology

•Preliminary results

•Conclusion and future work


Object of the investigationObject of the investigation

• Silicon diodes were fabricated simultaneouslyP-in-N N-in-P N-in-N

•Standard and oxygenated silicon

•Diodes were irradiated with 24GeV protons to fluences up to 1x1015cm-2

To understand influence of the fabrication technology in the radiation-induced degradation:


Pad detectorsPad detectors

•Mask designed by Liverpool•Area= 5x5mm2

•Guard ring=200µm•Thickness=280±15µm

N-in-P and N-in-Np-stop

1013 cm-3 1014 cm-3

Std Oxg Std Oxg

P-in-N

Std Oxg


Silicon Silicon MicrostripMicrostrip DetectorsDetectors

•770 strips diodes• 80 µm wide• 61570 µm long• polysilicon biasing resistors•Strips capacitively coupled

Mask set was designed between University of Liverpool and IMB-CNM


Technology: PTechnology: P--inin--N N

• Simple technology, only 5 mask levels.• Bulk inversion to p-type at around 2x1013 1 MeV n. equ. • Collection of holes.

P-in-N

N+ N

P+Guard ring

Inversion Layer


Technology: NTechnology: N--inin--P P

• More complex technology, 7 masks levels• Extra surface insulation, p-stop or p-spray• No type inversion expected• Collection of electrons

N-in-P

P+P

N+

P+ implant

Guard ring


Technology: NTechnology: N--inin--N N

• Complex technology, 10 mask levels• Both surfaces processing• Type inversion but at high radiation fluences

bulk silicon depletes from the N+ side • Collection of electrons after type inversion

N-in-N

N

N+

P+Guard ring

P+ implant


SimulationSimulation

0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,51E9

1E10

1E11

1E12

1E13

1E14

1E15

1E16

1E17

1E18

1E19

1E20

1E21

Con

cent

ratio

n(cm

-3)

Distance(µm)

Measurement Net concentration Boron concentration (after Annealing) Boron concentration (before Annealing)

Boron:Implantation energy=50KeVDose=4.2 *1015cm-3

•Spreading resistance

•Oxide charges 5x1011 cm-2

•Cylindrical coordinates

•Irradiation studies.

0 100 200 300 400 500 600 700

1E-13

1E-12

1E-11

1E-10

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

1E-3

Cur

rent

(A/c

m2 )

Bias(V)

Pad Simulation Pad experimental

0 50 100 150 200 250 3000,00

2,50x10-11

5,00x10-11

7,50x10-11

1,00x10-10

1,25x10-10

1,50x10-10

Cap

acita

nce(

F/cm

2 )

Bias(V)

Capacitance Simulation Capacitance Experimetal


CharacterisationCharacterisation

1) I-V: Leakage current measurements: Effect of the p-stop on N-in-P and N-in-N diodesBreakdown voltage.

2) C-V: capacitance measurementsfull depletion voltage

3) Radiation hardness: 2 parametersα: “damage” constantβ: the introduction rate of stable defects


Probe station IV and CVProbe station IV and CV

Karl Suss PA200

Low noise measurements


Measurements IV Measurements IV andand CVCV

1: Impedance Analyzer HP 4192A 2, 3: Keithley 2410 SourceMeter4: CERN Bench 5: RS Clock ThermometerCapacitance measured in parallelf=10kHz

4


Irradiation at CERNIrradiation at CERN

7.87E+137.87E+137.87E+13

2.70E+142.70E+142.70E+14

1.02E+151.02E+151.02E+15

7.73E+12-7.73E+12

0.00E+000.00E+000.00E+00

P-in-NN-in-PN-in-N •Protons 24GeV

•Diodes measured before annealing.

•Diodes irradiated without bias.

•Diodes stored at –35C.

•NIEL factor= 0.62 keVcm²/g

Fluences (protons/cm2)


Leakage current measurementsLeakage current measurements


Leakage current for Leakage current for PP--inin--N diodesN diodes


Leakage current for Leakage current for NN--inin--PP diodesdiodes


Leakage current for NLeakage current for N--inin--N diodesN diodes


Parameter Parameter αα

0,0 2,0x1014 4,0x1014 6,0x1014 8,0x1014 1,0x1015 1,2x10150,00

0,01

0,02

0,03

0,04

0,05

0,06

0,07

Cur

rent

Vol

ume

(A/c

m3 )

Fluence(proton/cm2)

P-in-N oxg. N-in-P oxg p-stop 1e13 N-in-N oxg p-stop 1e13

Currents were normalized to 20ºC according to equation: I~T2 exp(-E0/2kT) with E0=1.12 eV. ∆IVol=αφ


CV measurementsCV measurements

f = 10kHz


Full depletionFull depletion

VFD was extrapolated by crossing two straight lines in the logC-logV plot near the kink.


Full depletion vs. fluenceFull depletion vs. fluence

0,0 2,0x1014 4,0x1014 6,0x1014 8,0x1014 1,0x1015 1,2x10150

50100150200250300350400450500550600

0

1x1012

2x1012

3x1012

4x1012

5x1012

6x1012

7x1012

8x1012

9x1012

Effe

ctiv

e do

ping

con

cent

ratio

n N

eff (1

/cm

3 )

Full

depl

etio

n vo

ltage

(V)

Fluence φ (protons/cm2)

NP p-stop 10**14 (Std) NP p-stop 10**13 (Std) NN p-stop 10**14 (Std.) NN p-stop 10**13 (Std.) PN (Std.)

Standard Silicon

0,0 2,0x1014 4,0x1014 6,0x1014 8,0x1014 1,0x1015 1,2x10150

50100150200250300350400450500550600

0

1x1012

2x1012

3x1012

4x1012

5x1012

6x1012

7x1012

8x1012

9x1012

Effe

ctiv

e do

ping

con

cent

ratio

n N

eff (1

/cm

3 )

Full

depl

etio

n vo

ltage

(V)

Fluence φ (protons/cm2)

NP p-stop 10*14 (Oxg.) NP p-stop 10**13 (Oxg.) NN p-stop 10**13 (Oxg.) PN Oxg.

Oxygenated Silicon

The last two points in these plots were used to calculated the value of β.


Parameter Parameter ββ


Conclusions and future workConclusions and future work

Conclusions • Oxygenated detectors have low full depletion voltage after irradiation.• α is lower for N-in-N detectors• Detectors with p-stop of 1014cm-3 have breakdown voltages lower than

detectors with p-stop of 1013 cm-3.• N-in-P oxygenated detectors show a bulk inversion at a fluence of

2.7x1014 p/cm2

Future work:• Annealing studies• Charge collection efficiency• Measurements of microstrip• Simulation• Irradiation up to 1016 protons/cm2

comparison of radiation hardness of p-in-n, n-in-n …...giulio pellegrini cern-rd50 conclusions and...

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