y.unno, 4th workshop on advanced silicon radiation detectors, trento, italy, 17-19 feb., 2009 1...

Y.Unno, 4th Workshop on Advanced Silicon Radiation Detectors, Trento, Italy, 17-19 Feb., 2009 1

Development of Radiation-tolerant p-type Silicon Microstrip

SensorY. Unno

for

the joint collaboration of the R&D collaboration in Japan,

the ATLAS R&D collaboration of "Development of non-inverting Silicon strip detectors for the ATLAS ID upgrade", and

Hamamatsu Photonics K.K.


A Challenge Ahead• SLHC

– > x10 higher instaneous luminosity

• 300-400 pile-up events

• 20 (LHC)

– > x4 integrated luminosity

• 6,000 fb-1

• 700 fb-1 (LHC)

SCTPIXEL

• Particle fluences in ATLAS inner detector (ID)– ~1x1015 1-MeV neq/cm2 @ R ~30 cm, Z~150 cm

– Charged : n < 1:1– Neutrons: ~5x - 3x 1014 1-MeV neq/cm2 @ R ~30 cm - 90 cm


Some History of Development

• 2006 p-type 6-inch (150 mm) wafer (ATLAS06)– FZ1(100)(~6.7k Ωcm)– FZ2(100)(~6.2k Ωcm)– MCZ(100)(~2.3k Ωcm)

• 2007 p-type 6-inch (150 mm) wafer (ATLAS07)– FZ-1(100)(~6.7k Ωcm)– FZ-2(100)(~6.2k Ωcm)


ATLAS06 p-type Sensors• 6 inch (150 mm) wafer

– FZ1 (100), FZ2 (100), MCZ

• Many miniature (1cm x 1cm) sensors – One sensor per one

"Zone"

• Large (3cm x 6 cm) sensors with 2 striplets– Variation of Polysilicon

bias resistor connections

• R&D of n-strip isolation– Width of (common) p-

stop

– p-stop/p-spray doping concentrations


ATLAS07 p-type Sensors• 6-inch (150 mm) wafer

– FZ1, (FZ2)

• Full size (9.75 cm x 9.75 cm) prototype sensors– 4 segments: two "axial"

and two "stereo" (inclined) strips

• R&D's– n-Strip Isolation

– "Punch-thru Protection" structures

– Wide/Narrow metal effect

– Wide/Narrow pitch effect


Results of ATLAS06

• Evaluations– Irradiation at CYRIC (70 MeV protons)

• Fluences: 2, 5, 20, 30 x1014 1-MeV neq/cm2

– C-V and Laser (1064 nm)

• Results– FZ vs MCZ

• Full depletion voltages

• Annealing

– n-Strip isolation


FZ vs MCZ - FDV Development

• Proton damage• Full depletion

voltages (FDV)– Laser CCE

– (No MIP evaluation yet)

• No significant diffence is observed in FZ (FZ1 or FZ2) or MCZ

ATLAS06

CCE


FZ vs MCZ - Annealing

• Annealing– 2x1014

Samples

• Larger reverse annealing component in MCZ

C-V

Using fixed beneficial and reverse annealing time constants


0.00E+00

1.00E-06

2.00E-06

3.00E-06

4.00E-06

5.00E-06

0 200 400 600 800 1000

n-Strip Isolation

• Isolation voltage– at 10% over saturated current

• Degradation observed >2x1014 neq/cm2

– MCZ is the best

N+

P-bulk

SiO2

N+

1.5MΩ 1.5MΩ

AP-stop

Al

5VBias voltage


ATLAS07 1st batch - PTP mini

• PTP miniature sample– Onset of Microdischarge ~300V– Hot spot identified

• Source of trouble understood– TCAD simulation - 2nd p-stop– To be corrected in the mask

• Other zones (Z3) – Onset of MD >600 V

– Something else in trouble?


ATLAS07 1st batch - Main

• Main sensors– MD onset ~400 V

• Hot spot identified, Source of trouble understood - Asymmetric


TCAD Simulation - 2nd p-stop

• Y. Unno et al., IEEE08 Conf. record– Potential of 2nd p-stops makes

effective p-stop width as wide up to 2nd p-stop

– N-P gap was too narrow


TCAD Simulation - Asymmetric

• Wide pitch– Potential of p-stop is deep

• Asymmetric placement of p-stop– Potential of p-stop is nearly as

same as the symmetric– Electric field of the narrow gap

is steeper• Steeper than the same gap of

the symmetric placement of p-stop


ATLAS07-II• Onset of Microdischarge is expelled

>1,000V– not only diodes (bottom group) and

miniatures (middle group) – but also the main sensor (10 cm x 10

cm) (top line)!

• More than single sample– Two wafers are shown

• We/Vendor have established the basic technology

– of the radiation tolerant p-type sensor• that requires ~1,000V operation

– Now the issue is the "Yield" (in the vendor)

– For us, to validate the performance• After irradiation• Strip isolation• PTP protection


Measurement with -ray• Slit (0.5 mm) x

Absorber(0.5mm Al)– Trigger rate ~20 Hz

• 4 readout channels– Peaking time ~40 ns

90Sr : 2.28 MeV

= p/m = 5.4

0.5mmAl absorber

DUT

Sr90Sr90

Scinti

0.5mm

0.5mm

2mm

10mm

3.4mm

3mm

5mm

5mm

5 mm x 5 mm


Charge [fC]

Charge [fC]

No

. E

ven

tsN

o.

Eve

nts

ＨＶ＝１００　Ｖ

ＨＶ＝５８０　Ｖ

Collected Charge

CCE with

ＣＨ１

ＣＨ２

ＣＨ３

ＣＨ４

Event selection: "No signal" in CH1 and CH2(Cut: 0.6 fC)

Sum of CH1+CH2


CCE with • ATLAS07-II• Fluences

– p: 2, 5, 10 x10 １４

　 neq/cm2

– n: 2, 5, 10 x10 １４

　 neq/cm2

• Collected charges– of neutrons > of

protons– Something is

happening to neutrons?

– or to protons?– NO MD in I-V up

to the max. voltageH. Hatano et al. (U. Tsukuba+KEK)


CCE and FDV with Laser

• ATLAS07-II• Proton irradiation

– 0.15, 2.0, 5.0,10.0 x1014 neq/cm2

– Annealed for 80 min. at 60 °C

• Laser-CCE – beta-CCE to be made

soon

VmaxVmin(Pul

se h

eigh

t)^2

S. Mitsui et al. (U. Tsukuba + KEK)


CCE - Fluences and Radii

• beta-CCE (ATLAS07-II) Fluence dependence of neutrons and protons– seems different but needs further study– ~linear dependence on flunece

• CCE as a function of radius– >70% at 500 V, >80% at 800V


Strip Isolation - irradiation

• Degradation of strip isolation– Severe in < 2 kGy (< 200 krad)– Caution for the surface charge-up– (not shown but) MCZ seems worse than FZ

K.Hara et al., IEEE08 Conf. Record

ATLAS06 (FZ1) and ATLAS07-I (FZ1)


PT Protection

• ATLAS-II samples• Before irradiation

– V_ptp ~ 30 V (where the resistance becomes ~1/2)

• After p 1.0x1015 neq/cm2 – V_ptp ~ 30 V

M. Yamada et al. (U. Tsukuba + KEK)

Non irrad


Summary• Basic technology for the radiation tolerant p-type

silicon microstrip sensor is established– VMD > 1,000 V for a 10 cm x 10 cm large area sensor!

• No real advantage of the p-MCZ wafer to the p-FZ wafer, available in Japan– :-| Similar FDV development along irradiation– :-< Larger FDV till dominated by the radiation induced

acceptor components– :-< Larger reverse-annealing component– :-) Better strip isolation, but :-< rapid variation in irrad.

• CCE by n or p still has to be understood– Collected charges in neutron damage is larger than in proton

damage

• Evaluation with irradiation of ATLAS07-II has started


Backup


Proton Irradiation at CYRIC

• Facility associated with Univ. Tohoku, Sendai, Japan

Beamline 32

Beamline 31-2

KEK70 MeV protons


Proton irradiations at CYRIC• AVF Cyclotron at Tohoku University

– Beam energy: 70 MeV– Beam intensity: 10nA ~ 800nA– Beam spot size: ~5 mm FWHM

• ~4 min. for 1x1015 at 800 nA

• Irradiation history– Beamline 31-2

• 2005.10.17 - 1st and beamline study• ATLAS05 - up to 5x1015

– 2006.01.27 +2006.03.14 +2006.06.26 + 2006.10.16

• ATLAS06 - up to 2x1015

– 2007.05.18,

– Beamline 32– 2007.08.28

• ATLAS07 - up to 1x1015

– 2008.03.11

• Change of beamline– Machine time/user conflict in 31– Straight, simpler line in 32

Beamline 31-2

Beamline 32


Laser for FDV and CCE• Full Depletion Voltages (FDV)

– C-V method– Laser method

• Charge Collection Efficiencies (CCE)– Laser method

Pulsed laser (1064nm) focused to 4um x 4um

Referencesensor


I-V of Neutron-irradiated Samples

• n 1x1015 1-MeV neq/cm2 • No microdischarge up to 1,000V

y.unno, 4th workshop on advanced silicon radiation detectors, trento, italy, 17-19 feb., 2009 1...

Documents

development of radiation

cm2007 ptype

atlas06 ptype sensors6

atlas07 ptype sensors6inch

mev neqcm2 cv

mev protonsfluences

mcz cvusing

atlas id upgrade