10/09/2002 P. Roy

G. Pellegrini, A. Al-Ajili, L. Haddad, J. Melone, V. O'Shea, K.M. Smith, V. Wright, M. Rahman

Patrick Roy

Study of irradiated 3D detectors

10/09/2002 P. Roy

Overview

Introduction

Fabrication: -Dry etching -Laser machining -Photoelectrochemical etching -Electrical contacts

Results: -Before irradiation -After irradiation

Conclusion

10/09/2002 P. Roy

Introduction

10/09/2002 P. Roy

Motivation

Vdep qw2Neff/2

0 1 2 3 4 5 6 7 8 9 1 0

t i m e [ y e a r s ]

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

Vde

p (2

00

m)

[V]

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0s t a n d a r d s i l i c o n

o x y g e n a t e d s i l i c o n

operation voltage: 600 V

6000 e for B-layer 6000 e for B-layer

Damage projection for the ATLAS B-layer(3rd RD48 STATUS REPORT CERN LHCC 2000-009, LEB Status Report/RD48, 31 December 1999).

• 3D detector!

10/09/2002 P. Roy

Fabrication steps

Creation of the holes

Creation of the electrodes

Connection to the electronicsWire bondingBump bonding

Dry etchingLaser drillingPEC etching

Shottky-Schottkyn-Shottkyp-n junction

10/09/2002 P. Roy

Dry etching

•Diameter: 10 m•Spacing: 85 m•Depth: 130 m•Etch time: 100 minutes

Aspect ratio 13:1Expect < 20:1

Inductively Coupled Plasma

•Mask: photoresist•Gas: SF6

•Coating: C4F8

10/09/2002 P. Roy

Laser machining in SiTi:Sapphire laser (TOPS facility at Strathclyde University*)

3 mJ pulse with duration of 40 fs at 1 kHz repetition rate

810 nm wavelength or 405 nm wavelength (doubling crystal)

* In collaboration with D.A. Jaroszynski and D. Jones of Strathclyde University

•Diameter: Front: 8 -10 m Back: 6 - 8 m

•Spacing: 85 m

•Depth: 200 m

•Power: 75 mW

•Time: 5 sec/holes

Aspect ratio 25:1

10/09/2002 P. Roy

PEC etching in Si

Aspect ratio 12:1Expect > 100:1

•Diameter: 10 m•Spacing: 25 m•Depth: 120 m•Etch time: 480 minutes

•Mask: 100 nm l/s SiN•Solution: 2.5% aqueous HF

10/09/2002 P. Roy

Electrical contacts

•Tracks of Al (150 nm) (over the SiO2 layer)

•Metal evaporation:

Ti (33 nm)Pd (33 nm)

Au (150 nm) •Wire bonding(25 m wire)

10/09/2002 P. Roy

Results with particles5.5 MeV alpha in Si

0

40

80

120

100 150 200 250 300 350

Channel

Sig

na

l (c

ou

nts

)

45 V

50 V

70 V

80 V

5.5 MeV alpha in GaAs

0

10

20

30

40

50

60

70

80

50 100 150 200 250 300

Channel

Sig

na

l (c

ou

nts

)

10 V

30 V

50 V

120 V

Resolution~27%~54%

CCE~60%~47%

MaterialSiliconGaAs

Charge Collection Efficiency

0%

10%

20%

30%

40%

50%

60%

0 20 40 60 80 100 120

Bias (volts)

CC

ESilicon

GaAs

10/09/2002 P. Roy

Results with X-Ray in GaAs

0

200

400

600

800

1000

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0

Energy (keV)

Sig

nal

(co

un

ts)

Mo (17 keV)

Ag (22 keV)

Ba (32 keV)

Tb (45 keV)

Am (60 keV)

Resolution ~44%CCE ~70%

Tb (45 keV)

0

150

300

450

600

750

30 40 50 60 70 80 90 100

Channel

Sig

na

l (c

ou

nts

)

5 V

10 V

15 V

20 V

25 V

30 V

35 V

40 V

10/09/2002 P. Roy

Irradiation at PSI

Irradiation with 300 MeV/c at PSI (Villigen*)

Bunch of 1 ns every 19 ns.

Flux of 1014 /cm2/day.

Fluences between 1012 and 1014 /cm2.

Irradiation performed by K. Gabathuler, M. Glaser and M. Moll.

10/09/2002 P. Roy

Leakage currentBefore irradiation

-5.0E-05

0.0E+00

5.0E-05

1.0E-04

1.5E-04

2.0E-04

2.5E-04

3.0E-04

3.5E-04

-75 -50 -25 0 25 50 75

Bias (volts)

Cu

rren

t (A

)f = 1012 /cm2

-5.0E-05

5.0E-05

1.5E-04

2.5E-04

3.5E-04

4.5E-04

5.5E-04

6.5E-04

7.5E-04

-75 -50 -25 0 25 50 75

Bias (volts)

Cu

rren

t (A

)

f = 1014 /cm2

-1.5E-04

-1.0E-04

-5.0E-05

0.0E+00

5.0E-05

1.0E-04

1.5E-04

2.0E-04

2.5E-04

3.0E-04

3.5E-04

-100 -50 0 50 100

Bias (volts)

Cu

rre

nt

(A)

f = 1013 /cm2

-5.0E-05

0.0E+00

5.0E-05

1.0E-04

1.5E-04

2.0E-04

-35 -10 15 40 65 90

Bias (volts)

Cu

rren

t (A

)

10/09/2002 P. Roy

Fabrication comparison

Dry etchingLaser drillingPEC etching

Metal evaporationn or p type doping

13:125:112:1

<20:1~50:1

>100:1

Technique currently expected

Standard process

Expensive

Most promising

Sidewalldamages

yesyesno

Aspect ratios

Simple processComplex process

Good for GaAsGood for Si

10/09/2002 P. Roy

Conclusion

Dry etching ==> 13:1 in silicon

Laser machining ==> 25:1 material independent

PEC etching ==> 12:1 in silicon

Irradiated working devices in Si and GaAs

10/09/2002 P. Roy

In development

Run II with fs laser in GaAs and SiC

Improvement of PEC etching

Improvement of dry etching

Connection to DAC readout chip

Better contacts

Proton irradiation of samples