the mechanisms of photo-conversion in sipm elena popova moscow engineering and physics institute...

The mechanisms of

photo-conversion in SiPM

Elena Popova

Moscow Engineering and Physics Institute

Corsica meeting on fast timing

April 29-30, 2013

Corsica timing 29-30 April 2013E.Popova MEPhI

R 50

hpixel

U 60V

substrate

Each pixel – reverse biased above breakdown p-n-junction operated in selfquenching Geiger mode

Silicon Photomultiplier (SiPM)Multipixel device with common readout

Lets consider the way for SiPM signal


The way of signal. 1D

R

E

n

+ -

p

Ubias

1. Photoeffect (light absorption) - 0 time

2. Diffusion inside undepleted region (0 fields) - =L2/D D=38cm2/c L=1m 250ps

3. Drift in depleted region (low fields) 107 cm/c – saturated e- velocity x=3m t30ps

4. Avalanche build up (high fields) – several times*(3) T100ps

200 300 400 500 600 700 8001E-3

0,01

0,1

1

10

abso

rptio

n de

pth,

mic

ron

wavelenght, nm

13 m1m


1D simulation by using ISE TCAD.Diffusion from entrance window.

Laser pulse 10ps 400 nm (x0=100nm) Fixed intensity Reverse biased pn-junction

4000 200 600 Time, ps

Cur

rent

, A

0

1

2

3

4

Doping distribution and build-in fields are not constant

Should be weak sensitivity to applied voltages (depletion region should not changes much)

1) 0.1 25 702) 0.3 60 1503) 0.5 120 2004) 1.0 300 450

depth d, m Delay, ps FWHM, ps

Jitter component


Diffusion from substrate

Should be weak sensitivity to applied voltages (depletion region should not changes much)


Avalanche build up 1D

Impact ionization in high electric fields

electron hole

Ionization coefficient

Average number of ionization along carrier trajectory on unit lenght

Speed of avalanche build up depends from applied voltages and depletion region depth


All mentioned above points for 2D(3D) case

areas in pixel:1. Active central part of pixel2. Pixel’s perifery3. Interpixels area

1 and 2 – different•diffusion•Drift•Avalanche build up

1 2


Kj – vertical speed

u0 - transversal speed


Jitter should not depends on overvoltage!


34 36 38 40 42 44 46 48 50615

620

625

630

635

Chan

nel

Bias voltage, V

Delay of single pixel 50х50


I throw RL = 8mV/50OhM=160A

Current inside pixel Cpixel

Model Corsi with Transversal current expansion

Model for current expantion


Waveforms:1. Single pixel2. One pixel from 1x1mm2

SiPM the same topology

1

2


-30 -29 -28 -27 -26 -25 -24 -23 -22 -21 -20

-0,010

-0,005

0,000

Сигнал от лазера 405 нм на 50 Ом осциллографа. набор детекторов №1: S6N14, S6N15, S6n17, S6N20

U=? U=?V (забыл записать) 11.04.2013. N

pixel = 288

набор детекторов №2: S6N19, S6N21, S6n23, S6N24 U=26 U=3V 12.04.2013. N

pixel = 91

сигналы от двух наборов нормированы по амплитуде исовмещены по вершине импульса

Am

plit

ude, V

time, ns

Детекторы 3х3. 4 штуки объединены на одну нагрузку.SiPM06W14/15 50A2, pixel 50 um

20 21 22 23 24 25 26 27 28 29 30

-0,025

-0,020

-0,015

-0,010

-0,005

0,000

0,005

U=27 U=4VСигнал от лазера 405 нм на 50 Ом осциллографа.N

pixel = 35

Am

plit

ude, V

time, ns

Детектор 3х3 S6N24SiPM06W14/15 50A2, pixel 50 um

Model ExpDec2

Equationy = A1*exp(-x/t1) + A2*exp(-x/t2) + y0

Reduced Chi-Sqr

3,3801E-9

Adj. R-Square 0,99988

Value Standard Error

B y0 3,63869E-5 2,32842E-6

B A1 -0,02479 7,09765E-6

B t1 141,90739 0,07453

B A2 -1887,12656 593,43621

B t2 1,84327 0,04153

0 100 200 300 400 500 600 700 800 900 1000

-0,025

-0,020

-0,015

-0,010

-0,005

0,000

0,005

U=27 U=4VСигнал от лазера 405 нм на 50 Ом осциллографа.N

pixel = 35

Am

plit

ude, V

time, ns

Детектор 3х3 S6N24SiPM06W14/15 50A2, pixel 50 um

Model ExpDec2

Equationy = A1*exp(-x/t1) + A2*exp(-x/t2) + y0

Reduced Chi-Sqr

3,3801E-9

Adj. R-Square 0,99988

Value Standard Error

B y0 3,63869E-5 2,32842E-6

B A1 -0,02479 7,09765E-6

B t1 141,90739 0,07453

B A2 -1887,12656 593,43621

B t2 1,84327 0,04153

0 100 200 300 400 500 600 700 800 900 1000

-0,010

-0,005

0,000

Сигнал от лазера 405 нм на 50 Ом осциллографа. набор детекторов №1: S6N14, S6N15, S6n17, S6N20

U=? U=?V (забыл записать) 11.04.2013. N

pixel = 288

набор детекторов №2: S6N19, S6N21, S6n23, S6N24 U=26 U=3V 12.04.2013. N

pixel = 91

сигналы от двух наборов нормированы по амплитуде исовмещены по вершине импульса

Am

plit

ud

e, V

time, ns

Детекторы 3х3. 4 штуки объединены на одну нагрузку.SiPM06W14/15 50A2, pixel 50 um

3x3mm24* 3x3mm2


SPICE N=1000 pixels. Different Cfast

Current inside pixel Current on load


1x1mm2


SiPM readout

SiPM is a system of connected together pixels with one common readout pad

Metal buses – delay lines


Out-put

12


SiPM signal delay dependence on the SiPM chip area

0 5 10 15 20 250

200

400

600

800

1000

1200

De

lay,

ps

S, mm2


Timing by 5x5mm2 SiPM: a single phe resolutionFig.’s below show the impact of SiPM size(size of one pixel and SiPM itself)on

single phe resolution FWHM for SiPMs 1x1mm2(pixel size 25mkm) and 5x5mm2(pixel size 100mkm)

1000 1200 1400 1600 1800 2000

0

200

400

600

800

1000

FWHM=140 ps

Co

un

t

TDC channel (1 ch=5 ps)

1x1 mm2

576 pixels (25 m)

500 1000 1500 2000 25000

100

200

300

400

500

600

700

FWHM = 380 ps

5x5 mm2

1600 pixels (100 m)

Co

unt

TDC channel (1 ch = 5 ps)


Single µ-cell (100µm x 100µm) time resolution: 89 ps

For 1mm x 1mm size SiPM the time response is practically the same asfor the single µ-cell


0 5 10 15 20 25 30 35 40 450

20

40

60

80

100

120

140

160

180

200

220

240

B

Tim

e r

eso

lutio

n (

FW

HM

), p

s

dU/U,%

Single pixel response (MEPHI)


Main SiPM’s parameters. Jitter vs light intensity.

ADVANCED TECHNOLOGY & PARTICLE PHYSICS Proceedings of the 7th International Conference on ICATPP-7Villa, Olmo, Como, Italy, 15 - 19 October 2001

B.Dolgoshein et al.“THE ADVANCED STUDY OF SILICON PHOTOMULTIPLIER”

pheN

1~


SUMMARY How we obtain a signal from SiPM

1D case Photoeffect (0 time delta-function) Diffusion in undepleted regions Drift in depleted region Vertical build-up2D(3D) difference center-edge Transversal expansionElectrical signal propagation Total number of pixels in SiPM Signal readout Pixel position


IRST 1x1 MPPC 1x1

the mechanisms of photo-conversion in sipm elena popova moscow engineering and physics institute...

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