Silicon Photomultipliers and other advanced silicon sensors

The INFN MEMS project

R. BattistonINFN Perugia

March 12th 2007

The INFN MEMS project

The MEMS is a three years 8 M$ joint project within INFN and ITC-irst (Trento Italy), devoted to the development of innovative microelectronics silicon based devices using MEMS technologies

4 pilot projects are being developed since 2005, aiming to the developement of new types of radiation sensors for space based and ground based applications

1. Silicon Photomultipliers (for very low level photon counting)

2. Array of RF bolometers (for CMB next generation polarization detectors)

3. Cryogenic silicon detectors (for dark matter detectors) 4. 3D silicon detectors (for high rates silicon detectors)

MEMS MEMS

Pilot project #1 Development Pilot project #1 Development of SiPM detectorsof SiPM detectors

MEMS Project PAT-INFN

Al

ARC

-Vbias

Back contact

ppnn++

ppnn++

Rquenching

hh

p+ silicon wafer

Front contact

What is a SiPM ?

- Vbias

n pixels

One pixel fired

Two pixels fired

Three pixels fired

Current (a.u.)

Time (a.u.)

• matrix of n microcells in parallel

• each microcell: GM-APD + Rquenching

• originally developed by russian

groupsOut

The advantage of the SiPM in comparison with GM-APDANALOG DEVICE – the output signal is the sum of the signals from all fired pixels

SiPM – photon detector candidate for many future applicationsN. Dinu (Elba 2006)

S. Haino (INFN Perugia)

S. Haino (INFN Perugia)

A look on photon detectors characteristicsVACUUM

TECHNOLOGYSOLID-STATE TECHNOLOGY

PMT MCP-PMT HPD PN, PIN APD GM-APD

Photon detection efficiency

Blue 20 % 20 % 20 % 60 % 50 % 30%

Green-yellow 40 % 40 % 40 % 80-90 % 60-70 % 50%

Red 6 % 6 % 6 % 90-100 % 80 % 40%

Timing / 10 ph.e 100 ps 10 ps 100 ps tens ns few ns tens of ps

Gain 106 - 107 106 - 107 3 - 8x103 1 200 105 - 106

Operation voltage 1 kV 3 kV 20 kV 10-100V 100-500V 100 V

Operation in the magnetic field

10-3 T Axial magnetic field 2 T

Axial magnetic field 4 T

No sensitivity

No sensitivity

No sensitivity

Threshold sensitivity (S/N1)

1 ph.e 1 ph.e 1 ph.e 100 ph.e 10 ph.e 1 ph.e

Shape characteristics sensiblebulky

compact sensible, bulky

robust, compact, mechanically rugged

N. Dinu (Elba 2006)

Silicon Photomultiplier for the redout of a space born particle detector

(Perugia and Rome 2 INFN)-> 2005 first time in space! <-

The layout developed at ITC-irst (2005)

13

14

15

16

17

18

19

20

0 0.2 0.4 0.6 0.8 1 1.2 1.4

depth (um)

Doping conc. (10^) [1/cm^3]

0E+00

1E+05

2E+05

3E+05

4E+05

5E+05

6E+05

7E+05

E field (V/cm)

Doping

Field

n+ p Technology

Carachteristics1) Very thin window2) Optimized for the UV (420 nm)

Current structure:- pixel 1x1 mm2

- 25x25 microcells- single microcell: 40x40m2

1mm

1mmGeometry not yet optimized (geometrical factor today~ 30%) => to reach 45%

Geometry

Main blockWafer

Characterization

• Reverse IV measurement fast test to verify functionality and uniformity of the properties. (Performed on more than 1000 devices coming from 3 different batches)

• Dynamic characterization in the dark for a complete characterization of the output signal and noise properties (signal shape, gain, dark count, optical cross-talk, after-pulse) (performed on ~100 devices, coming from 2 different batches)

• Photodetection efficiency

• Energy resolution of SiPM coupled with LSO

• Timing performance

Single photoelectron resolution

ADC

Co

un

ts

1p.e.

2p.e.

3p.e.

Excellent singl photon resolution!

Single photon timing performance• Laser: - wavelength: 400 or 800nm - pulse width: ~60fs - pulse period: 12.34ns with time jitter <100fs• Filters: to have ~1 photodetection per laser pulse• SiPMs: 3 devices from 2 different batches measured

PRELIMINARY

12.34ns

tim

ing

sig

ma

(ps)

overvoltage (V)

1. More statistics needed2. New tests planned by the end of the year.

Photodetection efficiency

30

40

50

60

70

80

90

100

300 400 500 600 700 800Wavelength (nm)

QE (%)

0V

-2V

Simul

Simul ARC

0.00E+00

2.00E+00

4.00E+00

6.00E+00

8.00E+00

1.00E+01

1.20E+01

1.40E+01

1.60E+01

350 400 450 500 550 600 650 700 750 800

Wavelength (nm)

PDE (%)

36V

36.5V

37V

37.5V

38V

V=2V

2.5V

3.5V

3V

4V

QE vs Wavelength

long : low PDE becauselow QE

short : low PDE becauseavalanche istriggered byholes

Measured on a diode

Why this shape?

Reduced bysmall epi thickness

Reduced by ARC

Geometrical Factor ~ 20%

PDE=QE*Pt*GF

QE=quantum eff.Pt=avalanche prob.GF=geometrical factor

0.16

0.14

0.12

0.10

0.08

0.06

0.04

0.02

0

PD

E

350 400 450 500 550 600 650 700 750 800

Single SiPMs

Micro-pixel: 50x50m2

Fill factor: 50%

Micro-pixel: 100x100m2

Fill factor: 76% 1x1 mm2, 2x2 mm2

Micro-pixel: 40x40mm2Fill factor: 42% 1x1 mm2,

1.2 mm Ø

QE*pt ~ 60% @ 400 nm

PDE ~ 28 – 45 % @ 400 nm

New Perugia Wafer layout ( march 2007)

It includes:- square SiPMs with area: - 1x1mm2

- 2x2mm2

- 3x3mm2

- 4x4mm2

- circular SiPMs- linear arrays of SiPMs: - 1x8 - 1x16 - 1x32- 4x4 matrix of SiPMs

Scientific applications

Exploit your imagination !

Replace PM on – Scintillator readout for triggering and timing (eg. in

space, medical)– UV light detection from space– Cerenkov imaging for fast topological triggers– Fiber tracking– Calorimetry– ……………..

SiPM + Scintillator (DaSiPM)

Measurement set up:

- 1x1mm2 SiPM

- 1x1x10mm3 LSO scintillator (peak=420nm)

- Two SiPM, each one equipped with a LSO finger crystal directly positioned on the SiPM

- Measurement in Coincidence with a emitting 22Na source at 511keV)

1) Set up could be optimized

2) Geom factor to be optimized!

ResFWHM ~ 21%

ResFWHM ~ 29%

SiPM Geom factor ~ 20%

SiPM Geom factor ~ 30%

PRELIMINARY

New tests on 2x2 matrices are ongoing

Huge interest for these INFN detectors

INFN projects :• project DASiPM e DASiPM2 Medical PET• project SiRAD Space Radiation• project FACTOR Accelerator • project P-ILC calorimetry at ILCInternational projects :

• Fermilab for ILC calorimetr• CMS for HCAL outer barrel• Wolfson Brain Imaging Center, Cambridge for PET/MRI applications

Companies:• SIEMENS medical applications• PHILIPS medical applications• PHOTONIS for phtomultipliers• ISE srl per medical applications

Pubblicazioni INFN/ITC-irst (2006-2007)

• C. Piemonte “A new silicon photomultiplier structure for blue light detection” NIMA 568 (2006) 224-232• S. Moehrs et al. “Detector head design for small animal PET with Silicon Photomultiplier (SiPM)”, Physics in Medicine and Biology 51(2006) 1113-27.• D.J.Herbert et al.”First results of scintillator readout with Silicon Photomultiplier” IEEE Trans Nucl Sci 53(1), 2006,389-394. • D.J.Herbert et al. “Study of SiPM as a photodetector for scintillator readout” NIMA (2006) in press.• C. Piemonte et al. “Characterization of the first prototypes of silicon photomultipliers produced at ITC-irst” to appear on IEEE TNS February 2007• D.J.Herbert et al. “The Silicon Photomultiplier in high resolution gamma camera for PET applications” NIMA (2007) to be published.• N. Dinu et al. “Development of the first prototypes of SiPM at ITC-irst" NIMA (2007) to be published• F.Corsi et al “ Modelling a Silicon Photomultiplier (SiPM) as a signal source for optimum front-end design” NIMA (2007) to be published

• G. Llosa et al. “Novel silicon photomultipliers for PET application” CD Conference Records IEEE NSS and MIC 2006• C. Piemonte et al. “New results on the characterization of ITC-irst silicon photomultipliers” CD Conference records IEEE NSS and MIC 2006• C.Mazzocca et al.”Electrical Characterization of Silicon Photomultiplier detectors for optimal fornt-end design” CD Conference Records IEEE NSS and MIC 2006

Who is producing SiPM ?

In the ’90 russian groups:• JINR, Dubna• Obninsk/CPTA, Moscow• Mephi/PULSAR, Moscow

Since 2000 various european/japanese centers• Hamamatsu, Japan (available)

• SensL, Ireland (available)

• IRST/INFN, Italy (available)

• MPI, Germany (not available yet)

Official Website of MEMS INFN/IRST SiPM project: http://sipm.itc.it/

Final comments

A look to the future ……possible areas for collaboration among AMES and INFN

……….more and more integration among detectors and readout

3D electronics

R. Yarema

R. Yarema

R. Yarema

R. Yarema

Conclusions

MEMS detectors coupled with VLSI electronics, will be the basic blocks for more and more sensitive and compact detectors for ground based and space based applications where power and mass are of essence

With the MEMS project INFN and I are developing some among the most interesting technologies in this field (SiPM, bolometeres arrays)

INFN could collaborate with AMES on the future development in this field of intelligent compact detectors.