+

3rd.

CiRfSEWorkshopMeasurements of23-24 Jan. 2017

LGADS. Wada
The University of Tsukuba, B4+

Talk Outline

Brief Introduction of LGAD

IV Measurements (Pixel)
Setup description / Samples
 Wavelength Dependence of IV (Strip CV)

Temperature Dependence of IV

IV After Irradiation (Pixel)
-ray

Neutron2

+

3Low Gain Avalanche Detector


N+-on-PN+-P+-P--P+

Uniform high electric field@ N+-P+-junction (Thin multiplication layer)Avalanche
Good time resolution (~50ps)
AlP+

Insulator

N+P-well Layer

Low Gain (~10)

N+

Optimum S/NThinner detector
possibleP bulkP+ Electrode

Electric Field+

4

Samples from HPK

Pixel


Strip (chip size 6mm×12mm, strip 80m pitch)Pixel (chip size 2.5mm×2.5mm, window 1mm)Wafer No.

Dose
Gradations

PhysicalThickness (m)Active Thickness(m)Sample
Name

W02

A

W04(05)

B

50

50B

W07(08)C(3~8kcm)

50C

W10(11)

D

50A

50D
150

W13(14)A

W16(17)

B

80

80B

W19(20)C(1kcm)

80C

W22(23)

D80A

80D

N+Leakage

LED Light ResponseBlue (=464nm, D=0.5m)Green (=565nm, D=2m)

Red (=627nm, D=3m)Infra-red (=850nm, D=20m)

P+A

10−3Absorption Depth in Silicon

10−4
10−510−610−7P bulk

5IV Measurements ~ Setup

Absorption Depth [m]+10−8910−200
300 400 500 600 700 800 900 1000

P+ Electrode

Wavelength [nm]10−5Wavelength Dep. of IV (0~700V)
Pixel (active thickness 80m) @ 20
80A

Current [A]Current [A]+Infra-redRedGreen−61010−580B

1010−7Voltage [V]80C

Infra-red
RedGreen

10−610−510−7 Longer wavelength,080D



Infra-redRedBlue



0Voltage [V]Dose : A < B < C < D

Jumps @ ~30V

Breakdown Voltage

10−710−−8800 −700 −600 −500 −400 −300 −200 −100

higher gain

Green10−6Blue

Gain

Voltage [V]Current [A]Current [A]@ 10V (Gain~1)
10−−8800 −700 −600 −500 −400 −300 −200 −1000

Curves normalizedBlue

10−710−−8800 −700 −600 −500 −400 −300 −200 −10010−5

RedGreen−6Blue

Infra-red610−−8800 −700 −600 −500 −400 −300 −200 −1000Voltage [V]No Wavelength dep.

Wavelength Dep. of IV (0~100V)
Pixel (active thickness 80m) @ 20

10− 780A

Current [A]Current [A]+Infra-redRed
Green

5×10− 84×10− 8Blue

10− 780B
3×10− 82×10− 82×10− 8

5×10
4×10− 8

Blue

10− 7

Longer wavelength,0Higher gain

2×10− 82×10− 8

Infra-red

 More dose,

RedGreen

5×10
4×10− 83×10− 8080D−8

3×10− 810− 8−100 −90 −80 −70 −60 −50 −40 −30 −20 −10@ 10V (Gain~1)

Voltage [V]Current [A]RedGreen−8BlueHigher voltage@ ends of jumps

10− 8−100 −90 −80 −70 −60 −50 −40 −30 −20 −10

Voltage [V]0Voltage [V]Dose : A < B < C < D+Capacitance [F]Current [A]80C

Infra-red

Curves normalized More dose &10− 8−100 −90 −80 −70 −60 −50 −40 −30 −20 −100

RedBlue

Voltage [V]10− 7Infra-redGreen

5×10− 84×10− 83×10− 8

10− 8−100 −90 −80 −70 −60 −50 −40 −30 −20 −107P+ Dose Dependence of CVStrip 80m@ 1500Hz8−81080A

      




80B



80C−91080D

Depletion voltage
in agreement with IV

1st. Depletion
Electrode side way



2nd. Depletion

3rd. Depletion−10Multiplication layer

10Bulk’s depletion
10−−11100 −90 −80 −70 −60 −50 −40 −30 −20 −10
Dose : A < B < C < D

0Voltage [V]10−50 °C
20 °C
40 °C
60 °C


10−610−50 °C
20 °C
40 °C
60 °C


10−610−7

10−710−−8800 −700 −600 −500 −400 −300 −200 −100010−−8800 −700 −600 −500 −400 −300 −200 −100Voltage [V]0Voltage [V]Green LED Light Response
+9Temperature Dependence of IVPixel 50m & 80m @ 20
Current [A]Current [A]+Lower temp., larger currentAvalanche

10IV After -ray Irradiation@ 20

10−510−650D

Leakage [A]Leakage [A] 
Non-Irradiated
0.1MGy1.0MGy2.5MGy10−510−610−710−710−810−810−910−910−10−800 −700 −600 −500 −400 −300 −200 −100

80D10

50D−510−61010−710−710−810−8Non-Irradiated10−901.0MGy
2.5MGy0Voltage [V]1.0MGy



2.5MGyLeakage increase
no dose independence

because of surface damage
Green LED response

not changed

0.1MGy1.0MGy2.5MGy10−10−800 −700 −600 −500 −400 −300 −200 −1000.1MGy

80D

Non-Irradiated10−90.1MGy



Voltage [V]Current [A]Current [A]−624 Nov. - 20 Dec. 2016

−5101.0MGy
2.5MGyVoltage [V]   

0.1MGy10−10−800 −700 −600 −500 −400 −300 −200 −1000TARRI(QST), Japan

Non-Irradiated10−10−800 −700 −600 −500 −400 −300 −200 −1000Voltage [V]Gain retain

+@ 20

−510

Leakage [A]Leakage [A] 
0D−61010−780D−610−8

Anneal 0min.

10

Anneal 20min.

Anneal 20min.
Anneal 40min.

−9

Anneal 60min.

Non Irad0−10

10 −800 −700 −600 −500 −400 −300 −200 −100

Voltage [V]   


Current [A]Anneal 0min.
Anneal 20min.

0.08

Anneal 40min.
Anneal 60min.

0.07

Anneal 80min.
Non Irad0.06



Leakage increaseGain retain

Anneal 0min.

0.09

Anneal 20min.

0.08

Anneal 40min.
Anneal 60min.

0.07

Anneal 80min.
Non Irad

0.06
0.05

0.04

0.04

0.03

0.03

0.02

0.02

50D0.01

Annealing @ 60

3.0×1015neq/cm2

0.1×100.05

0−800 −700 −600 −500 −400 −300 −200 −100
0−60.09

1.0×1015neq/cm2Voltage [V]−60.1×10



Anneal 80min.

Non Irad−1010 −800 −700 −600 −500 −400 −300 −200 −100

0.3×1015neq/cm2

Anneal 60min.

10

Anneal 80min.

Anneal 0min.

Anneal 40min.

−910Current [A]

15 Dec. 2016

10−8+Ljubljana, Slovenia−510−7100.01

appear @ higher voltage

e.g. 50D (280V700V)

Gain ~580D

0−800 −700 −600 −500 −400 −300 −200 −1000

Voltage [V]0Voltage [V]@ 20

Leakage [A]Leakage [A]−510

0D−61010−780D−61015 Dec. 2016

10−8−8Anneal 0min.

10

Anneal 20min.

Anneal 20min.
Anneal 40min.

−9Anneal 60min.

Non Irad0−10

10 −800 −700 −600 −500 −400 −300 −200 −100

Voltage [V]   0
Current [A]50D

Anneal 20min.
Anneal 40min.
Anneal 60min.

0.07
0.06

Anneal 80min.
Non Irad

0.09
0.08

Leakage increase

0.05

0.04

0.04

0.03

0.03

0.02

0.02Annealing @ 60

80D

Gain disappear? (< 800V)

Anneal 0min.
Anneal 20min.
Anneal 40min.
Anneal 60min.

0.07

0.05

Anneal 80min.
Non Irad0.01

0−800 −700 −600 −500 −400 −300 −200 −1000

Voltage [V]

3.0×1015neq/cm2

0.1×10

0.06

0.01




−6

Anneal 0min.

1.0×1015neq/cm2

Voltage [V]−60.1×10



Anneal 80min.

Non Irad−10

10 −800 −700 −600 −500 −400 −300 −200 −100

0.3×1015neq/cm2

Anneal 60min.

10

Anneal 80min.

Anneal 0min.

Anneal 40min.

−910

Current [A]Ljubljana, Slovenia−510−7100.08

12IV Annealing After Neutron Irradiation3.0×1015neq/cm2 0.09

11IV Annealing After Neutron Irradiation1.0×1015neq/cm2

0−800 −700 −600 −500 −400 −300 −200 −1000Voltage [V]+Conclusions / Future Work Understood the structure of LGAD from HPKGain retain after -ray irradiation (2.5MGy)

After neutron irradiation, (1.0×1015neq/cm2) gain retain(3.0×1015neq/cm2) gain disappear (< 800V)

Measure Laser & -ray ResponseProton Irradiation (Feb. 2017 @ CYRIC)

13