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Study of irradiated 3D detectors. Patrick Roy. G. Pellegrini, A. Al-Ajili, L. Haddad, J. Melone, V. O'Shea, K.M. Smith, V. Wright, M. Rahman. Overview. Introduction Fabrication: -Dry etching -Laser machining -Photoelectrochemical etching - PowerPoint PPT Presentation
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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