1. Centro Nacional de Microelectrónica (IMB-CNM-CSIC)
New detectors development at CNM-IMB
G. Pellegrini
Centro Nacional de Microelectrónica (IMB-CNM-CSIC)
Barcelona, Spain

2. CNM Research Projects in HEP
Coordinador
Main exp.
SCTESP4
(M.Ullan) IFIC ATLAS upgrade
NEWATLASPIX2
(G. Pellegrini) IFAE ATLAS IBL
DET4HEP
(S. Hidalgo) IFCA CMS-ILC
All the projects are linked by the development of new advanced detector technologies for the different applications

3. SCTESP4 Contribution to the ATLAS Experiment Upgrade for the S-LHC
Objective:
Technological developments associated with the ATLAS Upgrade for the Super-LHC at CERN. Working in two fronts: On one side in the development of radiation detectors that will maintain the current performances after the increase of one order of magnitude in the luminosity at S-LHC. On the other side, in the search of suitable readout electronics for these detectors and the proper power distribution.
Project ends December 2012

4. Radiation hardness studies
Front-end electronics detailed technology evaluation
Proposal and full assessment of one advanced technology
Design of test chips
Ionization, displacement
Dose Rate (ELDRS)
Radiation hardness evaluation of LDMOS power devices for DC-DC power distribution
Test
Simulation

5. Prototype detector fabrication
For the modules prototypes of the End-Cap Inner Tracker
Addresses most of the issues that make a petal different than a stave.
Built-in stereo angle.
Different pitch.
Bonding angle.
Embedded pads.
Incomplete strips
Automatic detector layout construction tool
Sensors being fabricated for a total of 10 prototypes (60 sensors)

6. New detectors development – RD50
Bias rail
Polysilicon “bridge/gate”
Implant
Low resistance strip sensors
Full protection vs. beam loss
Punch-Through Protection (PTP) optimization
Deposition of Aluminum on top of the implant
Combined experiment with Slim Edges (Trenches 30 um wide):
Opt 1: 10 μm deep etch
Opt 2: ~ μm deep etch
Opt 3: XeF2 etch at NRL

7. NEWATLASPIX2
Development and construction of pixel detectors for the IBL and sLHC ATLAS experiment upgrades
Objective:
Contribute to various aspects of the development of pixel sensors for the IBL (insertable b-layer) of the ATLAS Inner Detector and the sLHC.
Project ends December 2013

8. IBL Production 50% of IBL 3D sensors fabricated at CNM.
255 detectors delivered to IZM for the UBM and flip chip.
Common layout within the the Atlas 3D collaboration (
Sensors produced for the geometry of the FE-I4 chip:
50um x 250um
210um columns in 230um p-bulk
Inactive edges of ~ 200 um
Extensive characterization and testing being done at IFAE with un-irradiated and irradiated devices up to 5.11x 1015 neq/cm2

9. Technology:

10. Test-beam Results
CNM devices have been tested in the CERN testbeam and have shown efficiencies >97% after irradiation (according to IBL specifications)
Pixel efficiency map: fold efficiency to 1 (±0.5) pixel
(match track in 3x3pixel window)
CNM55: un-irradiated
0deg incidence
HV=20V
eff=99.4%
CNM81: n-irradiated
0deg incidence
HV=160V
eff=97.5%
Resolution:
Spatial resolution is mainly determined by the pixel pitch, but the choice of readout mode (analog or binary), the reconstruction algorithm and the amount of charge sharing also play a role.
50um/sqrt(12)=14um
But the resolution is for 2 pixel clusters, then the resolution would be s/sqrt(12), where s is the width of the 2 pixel hit region (which can be estimated from the cluster size distribution).
So, if we say that the s=50% x 50um=> the resolution should be=0.5x50/sqrt(12)=7um. And if I add the 4um track contribution from the telescope => ~8um…
CNM34: p-irradiated
15deg incidence
HV=160V
eff=98.9% 10

11. Work plan

12. R&D on detectors for future colliders
DET4HEP
R&D on detectors for future colliders
Objective:
Development of new tools, technologies and techniques to bring new detector concepts to the stage where they can be considered for new or existing facilities.
Project ends December 2013

13. Silicon APDs Linear mode RT-APD First experimental results
N on P Reach-Through Avalanche Photodiodes
Active area: 5 × 5 mm2
Dice Area: 8 × 8 mm2
Device thickness: 300 µm
N+ cathode
P-type layer:Different Boron doses
Different layouts with and w/o guard ring, with non-metalized windows for laser characterization
P-type substrate: ρ = 5-15 kΩ·cm
P+ anode
First experimental results
VFD < 30 V
VBD > 1100 V
Problems to overcome 200 V for encapsulated devices
I ~ ºC

14. Thinned microstrips sensors with integrated pitch adapters
5 wafers thinned to 100um thick.
6 thick wafers 285 um.
AC strip detectors, 80um pitch.
Double metal technology to implement integrated fanout.
Detectors to be irradiated.

15. Detectors with Fiber Optic Sensors (FOS)
Grooves for optical fibres
Fiber Bragg grating (FBG)
L. Benussi et al., Proc. IEEE Sensors 2 (2002), 874
Optical fibre were successfully inserted and clamped
Bridges
Clamps
500um
Ideal candidate for present and next generation HEP detectors especially due to compactness, easy installation, high level performance, multifunctionality, expected radiation hardness and flexibility

16. CMS pixel detectors 8 wafers already fabricated and tested at CNM.
See Paki´s talk
8 wafers already fabricated and tested at CNM.
PSI already bonded many devices
Detector bonded sent for irradiation at Karlsruhe and Ljubljana (Φ= 1x1015, 5x1015 y 1x1016 n/cm². )
Full- Module

17. What can be improved in pixel detectors for HEP or other applications?
Short term: slim edges
Long Term: thin substrates with charge multiplication

18. 1) Post processing for slim edges
Reduce the dead area at the detector edges. Laser-Scribing and Al2O3 Sidewall Passivation of P-Type Sensors.
Negative charges induced by Al2O3 deposited by ALD process, isolate the sidewall surface cut in p-type wafers reducing surface current.
Laser cutting and ALD done at NRL
Marc Christophersen
Work done in the framework of RD50 collaboration (CERN)

19. Pixel Status: AFP (TOTEM?)
Pixel detectors: technology choice in high-energy physics for innermost tracking and vertexing.
AFP: detect very forward protons at 220m from IP, with pixel detectors for position resolution and timing detectors for removal of pile up protons.
Both Si and timing detectors mounted in movable beam pipe
Silicon detector has to have small dead inactive region on side into beam
Non-uniform irradiation of the detectors.
420m and 220m…
220m to ATLAS P1 19

20. Slim edges Dicing process
P-Type Silicon
Annealing of alumina layer reduces leakage current (same effect as seen for solar cells).
Formation of native oxide (wrong surface charge) ↑ leakage current.
Native oxide forms rapidly (within seconds/minutes) in air.
Native oxide: ~ 2 nm thick, high charge trap density.
Laser-scribing and cleaving common in LED industry
Automated tools for scribing and breaking of devices on wafer-scale

21. New samples with slim edges (Atlas FE-I4 pixels)
Laser cutting and ALD done at NRL
55um
Spare 3D FE-I4 detectors from IBL production done at CNM. Normally from damaged wafers.

22. In-Homogeneous Irradiation and Test-beam Results
AFP devices will receive an in-homogeneous irr. dose (up to 2E15 neq/cm2)
Irradiation done at CERN (24 GeV protons)
IBL-sensors were irradiated ‘a la-AFP’ and their performance evaluated with beam
Work done with the ATLAS IBL, 3D and AFP groups
CERN 3D Testbeam
Preliminary efficiency: 98.3%
Operated at 130V
Beam pointing to “irradiated side”
Cooled with dry-ice (-30C)
Preliminary results for CNM(57) device
S. Grinstein presented at RESMDD12

23. Charge Multiplication- pixel detectors
We are on the fabrication of new p-type pixel detectors with enhanced multiplication effect in the n-type electrodes.
3 different approaches:
Thin p-type epitaxyal substrates
Low gain avalanche detectors
3D with enhanced electric field.
I am coordinating two RD50 projects (under approval) to work on these technologies.

24. 1)Thin p-type epitaxyal substrates
Detector proposed by Hartmut Sadrozinski and Abe Seiden (UCSC) , Ultra-Fast Silicon Detectors (UFSD).
Provide in the same detector and readout chain
Ultra-fast timing resolution [10’s of ps]
Precision location information [10’s of µm]
We propose to achieve high electric field is to use thin p-type epitaxyal substrates [1] grown on thick support wafers, p+-type doped, that acts as the backside ohmic contact. Different thicknesses will be used to study the multiplication effect induced by the high electric field at the collecting electrodes, depending on availability we propose to use: 10, 50, 75µm. Need very fast pixel readout.
H. Sadrozinski, “Exploring charge multiplication for fast timing with silicon sensors” 20th RD50 Workshop, Bari 2012

25. 2)Low gain avalanche detectors (LGAD)
Crating an n++/p+/p- junction along the centre of the electrodes. Under reverse bias conditions, a high electric field region is created at this localised region, which can lead to a multiplication mechanism. N+ P
High Electric Field region leading to multiplication
285 um
P. Fernandez et al, “Simulation of new p-type strip detectors with trench to enhance the charge multiplication effect in the n-type electrodes” , Nuclear InstrumentsandMethodsinPhysicsResearchA658(2011) 98–102.

26. 3) 3D with enhanced electric field
Simulation has shown that using silicon substrates with a resistivity <500ohm*cm could induce charge multiplication at low bias voltage but still depleting the detector bulk.
We are ready to start the production on SOI wafers (resistivity 100ohm*cm) with a thickness of 50µm to fabricate 3d thin detectors with medium or low multiplication factors before irradiations.
J.P Balbuena, Simulation of 3D detectors, 6th Trento Workshop on Advanced Radiation Detectors, 2-4 March 2011 FBK, Povo di Trento, Italy

27. Conclusions Future Work Continue with the collaborations established.
Collaboration between CNM and HEP institutes is working very well.
Collaboration between “Technology” and “Physics” is very important to propose new technologies for future colliders.
At Barcelona we have created a the full chain for sensor production, assembly and testing available.
Future Work
Continue with the collaborations established.
Start fabrication of detectors in 6” wafers.
Slim edges (or active) and charge multiplication effect.