LASER MICRO-MACHINING FOR 3D DIAMOND DETECTORS APPLICATIONS · PDF [email protected]...

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LASER MICRO-MACHINING FOR 3D DIAMOND DETECTORS

APPLICATIONS

1st ADAMAS WORKSHOP | 17 DEC 2012

B.Caylar1, M.Pomorski1, D.Tromson1, P.Bergonzo1, J.Alvarez2, A.Oh3,C. Da Via3 , I.Haughton3, V.Tyzhnevy3, T.Wengler4

1CEA-LIST, French Atomic Energy Commission, France

2 Laboratoire de Génie Electrique de Paris , France

3 University of Manchester, School of Physics and Astronomy, Manchester, UK

4 CERN, 1211 Geneva 23, Switzerland

[email protected] 1st ADAMAS WORKSHOP | 17 DEC 2012 2

CONTEXT Diamond detectors in High Energy Physics

All LHC experiments already use diamonds for beam monitoring or as pixel detectors

CMS is building Pixel Luminosity Telescope

» 48 scCVD pixel modules (5 mm x 5 mm)

ATLAS is building Diamond Beam Monitor

» 24 pCVD pixel modules (21 mm x 18 mm)

Upgrade plans include diamond as candidate

for innermost pixel tracker layer(s) Marko Mikuž “Diamond Sensors”, ICHEP (2012)

Beam Monitors

Pixel Detectors

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CONTEXT Luminosity previsions

At LHC, luminosity will increase more and more in the following years


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0 5 10 15 20 250

1

Collected charges [ke]

4

CONTEXT Radiation hardness is still an issue in diamond

NIEL induces bulk defects…

Higher luminosity

» Faster signal decrease

Development of advanced detectors

» Diamond detectors

» Silicon 3D detectors

Why won’t we try to build the radiation hardest

detector ever ? A 3D Diamond Detector…

Signal

decrease

Before irradiation

After 1.2 x 1014 n.cm-2

After 1.97 x 1014 n.cm-2


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Planar geometry

QMIP = 18000 e-h pairs

3D geometry


5

CONTEXT What is a 3D detector ?

Analytically calculated currents generated by a MIP

0 2 4 6 80,0

0,2

0,4

0,6

0,8

1,0

Cu

rren

t [µ

A]

Time (ns)

Average Lifetime = 250ns


-0,2 0,0 0,2 0,4 0,6 0,80,0

2,5

5,0

7,5

10,0

12,5

15,0

Cu

rre

nt

[µA

]

Time (ns)



500µm

50µm


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Planar geometry


3D geometry


6

CONTEXT What is a 3D detector ?

0 2 4 6 80,0

0,5

1,0

1,5

2,0

2,5

3,0

Co

llecte

d C

ha

rge

(fC

)

Time (ns)


Average Lifteime = 2ns

CCE drops

by 53%

0 2 4 6 80,0

0,5

1,0

1,5

2,0

2,5

3,0

Co

llecte

d C

ha

rge

(fC

)Time (ns)


Average Lifteime = 2ns

CCE drops

by 5%

500µm

50µm

Analytically calculated charge collection


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BURRIED ELECTRODES Laser setup and fabrication

Electrodes are processed using laser-induced graphitization

Wavelength : 800nm

Repetition rate : 1kHz

Pulse length : 100fs

Spot size : 10µm


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YAG Laser » Hollow, conical shape

» Diameter : 100µm

» Pitch : 300µm

8

Laser setup and fabrication

Process improvement over the past two years

BURRIED ELECTRODES

100µm

Dec 2010

Feb 2011

Jun 2011

Apr 2012


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UV Laser + x10 Lens » Diameter : 75µm

» Pitch : 200µm

9



BURRIED ELECTRODES

Dec 2010

Feb 2011

Jun 2011

Apr 2012


100µm

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UV Laser + x20 Lens » Diameter : 20µm

» Pitch : 150µm

10



BURRIED ELECTRODES

Dec 2010

Feb 2011

Jun 2011

Apr 2012


100µm

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Femtosecond laser » Diameter : 5µm

» Pitch < 35µm

11



BURRIED ELECTRODES

100µm 100µm

100µm 100µm Dec 2010

Feb 2011

Jun 2011

Apr 2012


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A two-step process

Producing a graphitic seed at the surface

» Excitation of a large number of valence electrons via multi-photon absorption

» Energy barrier decreases

» Phase transition Diamond- Graphite

Propagation of laser supported graphitic wave

12

BURRIED ELECTRODES Why is femtosecond laser so much better ?

No heat

accumulation

T.V. Kononenko et Al – Rus’nanotech (2010)


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BURRIED ELECTRODES Structural characterization

Raman Analysis

EHT = 5kV WD = 4.9mm Mag = 11.85k X

1000 1200 1400 1600 1800 20001

10

100

1000

Inte

nsity (

a.u

)

Wavenumber (cm-1)

Border

1000 1200 1400 1600 1800 20001

10

100

1000

Inte

nsity (

a.u

)

Wavenumber (cm-1)

Diamond

1000 1200 1400 1600 1800 20001

10

100

1000

Inte

nsity (

a.u

)

Wavenumber (cm-1)

1595 cm-11332.24 cm-1

Electrode


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AFM mapping

14


1µm 1µm

Electrode mapping using Conductive probe AFM

Resistance mapping


R

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Resistance distribution in the mapping area

15


1µm 1µm

Electrode mapping using Conductive probe AFM

Resistance mapping

200 kΩ

ρ ~ 1 Ω.cm


R


3D DIAMOND DETECTOR Final detector

scCVD sample

Courtesy of CERN

Optical microscopy


50µm

125µm

Rectangular

unit cell



» Graphitization process wasn’t optimized – 70% success rate

scCVD sample

Courtesy of CERN


50µm

125µm

Rectangular

unit cell

Optical microscopy – Crossed polarizers (Surface)




scCVD sample

Courtesy of CERN


50µm

125µm

Rectangular

unit cell

Optical microscopy – Crossed polarizers (In Bulk)




scCVD sample

Courtesy of CERN


50µm

125µm

Rectangular

unit cell

Optical microscopy – 45° Tilt


3D DIAMOND DETECTOR

Electrical characterization


I(V) measurement

-150 -100 -50 0 50 100 150 200

-0,4

-0,2

0,0

0,2

0,4

0,6

Increasing voltage

Decreasing voltage

Curr

en

t (n

A)

Voltage (V)


3D DIAMOND DETECTOR Characterization using protons micro-beam

Experimental setup @IRB, Zagreb – 4,5 MeV protons µ-beam (1µm resolution)



3D DIAMOND DETECTOR

Characterization using protons micro-beam


IBIC mapping

HV = +1V

» The dead area is due to a broken strip


3D DIAMOND DETECTOR



IBIC mapping

HV = +1V

» All connected colums are active


3D DIAMOND DETECTOR



IBIC mapping – Increasing positive bias

+1V

+40V +100V

+5V

» CCE is strongly non uniform


3D DIAMOND DETECTOR



IBIC mapping – Increasing negative bias

-1V

-40V -100V

-5V

» Similar behaviour with negative polarity

» Probably due to bad contact (Al) quality


3D DIAMOND DETECTOR



IBIC mapping – Charge Collection efficiency spectra

Negative biases Positive biases

0 5000 10000 15000 20000 25000 300000,0

0,2

0,4

0,6

0,8

1,0

No

rma

lize

d C

ou

nts

ADC Channels

+1V

+5V

+40V

+100V

0 5000 10000 15000 20000 25000 300000,0

0,2

0,4

0,6

0,8

1,0 -1V

-5V

-40V

-100V

No

rma

lize

d C

ou

nts

ADC Channels


3D DIAMOND DETECTOR



IBIC mapping – Focusing on a high CCE area

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0 5000 10000 15000 20000 25000 300000,0

0,2

0,4

0,6

0,8

1,0

Norm

aliz

ed

Coun

tsADC Channels

+1V

+5V

+40V

+100V

0 5000 10000 15000 20000 25000 300000,0

0,2

0,4

0,6

0,8

1,0

Norm

aliz

ed

Coun

ts

ADC Channels

-1V

-5V

-40V

-100V

28

3D DIAMOND DETECTOR



IBIC mapping – Focusing on a high CCE area

Negative biases Positive biases


3D DIAMOND DETECTOR Characterization using synchrotron micro-beam

Mapping using 11.5keV photons (10µm resolution)


» Response homogeneity is OK

» There are hot spots that need to be investigated (material related)

HV = +10V

-8,1 -8,0 -7,9 -7,8 -7,7 -7,6 -7,5 -7,4-1,3

-1,2

-1,1

-1,0

-0,9

-0,8

-0,7

-0,6

X Position (mm)

Y P

ositio

n (

mm

)

1,0E+04

2,0E+04

3,0E+04

4,0E+04

5,0E+04

6,0E+04

-7,7 -7,6 -7,5 -7,4

-1,1

-1,0

-0,9

-0,8

X Position (mm)

Y P

ositio

n (

mm

)

1,0E+04

2,0E+04

3,0E+04

4,0E+04

5,0E+04

6,0E+04


3D DIAMOND DETECTOR Summary

We managed to…

Produce graphitic electrodes with suitable dimensions for detectors applications

Check that electrodes conductive enough and allow 100% CCE

Check that device can be used in both single particle and DC measurements

Now we need to…

Optimize contacts (see Alex talk)

Understand these hot spots

Irradiate samples and measure their radiation hardness



Thanks for your attention !



3D DIAMOND DETECTOR Acknowledgements

External co-workers

Cinzia Da Via

Lin Li

David Whitehead

Thorsten Wengler

Natko Skukan

Veljko Grilj

Milko Jakšić

Stéphanie Hustache

Kewin Desjardins

People @ CEA-LIST

Nicolas Tranchant

Hassen Hamrita

Nicolas Vaissière

Céline Gesset


LASER MICRO-MACHINING FOR 3D DIAMOND DETECTORS APPLICATIONS · PDF [email protected]...

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