1. FBK / INFN Roma, November , 17th 2009 G. Darbo - INFN / Genova
3D Sensor FBK
FBK / INFN
Roma, November , 17th 2009
G. Darbo - INFN / Genova

2. ATLAS Pixel Detector ATLAS Pixel Detector:
3 Barrel Layers + 3 forward and backward disks.
1744 modules with 16 chips (27904 FE-I3 chips) – 1.7 m2 of active area

3. Present ATLAS Pixel Detector
ATLAS Pixel Module
1744 Modules x 16 FE-I3 chips
16.8x60.4 mm2
Sensor
n-in-n oxygenated
1x1015 neqcm-2
FE-I3
0.13µm CMOS
3.5 million transistors

4. ATLAS Pixel Pictures
Bi-stave with 26 modules
Layer2 half shell

5. ATLAS Upgrade Plans: IBL
Add a new layer of Pixel inside the present three layers of the detector:
14 staves with 16 (or 32) double (single) chip modules.
Prototype 2010, production 2011÷12
FE-I4 chip: ~2x2 cm, 250x50 µm pixel size
New FE-I4
Pixel size = 250 x 50 µm2
Pixels = 80 x 336
Technology = 0.13µm
Power = 0.5 W/cm2
FE-I3
active
16.8mm
20.2mm
~2mm
~200μm
FE-I4
~89%
Chartered reticule (24 x 32)
IBM reticule
~19 mm
7.6mm
8mm
active
2.8mm
FE-I3
74%

6. FE-I4 FE-I3 not suitable for IBL
~7% inefficiency at 3.7 cm and L = 3x1034 cm-2s-1
FE-I3 works at 50 Mrad, but has major faults at 100 Mrad
FEI4 design collaboration formed in 2007 between:
Bonn, CPPM, Genova, LBNL, NIKHEF
FE-I4_proto chip (3/08)
Main analog blocks (3x4mm2)
Irradiated to 200 Mrad: noise increase by 20% (ENC 100 120 with 400fF load and IAVDD=10µA/pixel)
FE-I3 Inefficiency

7. IBL Requirements for Sensors/Electronics
Requirements for IBL (sensors/electronics)
IBL design Peak Luminosity = 3x1034 cm-2s-1  New FE-I4, higher hit rate
Integrated Luminosity seen by IBL = 550 fb-1
Total NIEL dose (rmin=3.1cm): Φ1MeV = 3.1 x 1015 ± 30% (σpp) ± 50% (sensor damage factor)
Safety factor for IBL (60%)  design for 5 x 1015 neq/cm2  more rad-hard sensors
Total ionization dose (TID) > 200 Mrad
ATLAS Pixel Sensor/FE-I3 designed for neq/cm2 / 50 Mrad
1MeV and TID for integrated luminosity of 1000 fb-1
Ref. Ian Dawson – ATLAS IBL General Meeting (25-26 June 09)

8. 3D Sensors - Test Beam
Jun.09 test beam: 1 ATLAS Pixel planar, 1 3D SINTEF/Stanford (full column), 2 FBK partial double columns (FBK 3EM5 has low 10V)
For inclined tracks 3D sensors have similar efficiency and spatial resolution as planar – No Lorentz angle effect in 3D sensor
Active edge (STA) show efficiency up to 5÷10µm from edge
Very good collaboration between all 3D sensor producers:
Two meetings (Jun’09, Sep’09)
They look for collaboration more than competition: better chances for IBL of having compatible 3D design in time!
Ref.: O. Rohne – Vertex 2009

9. Assemblies
Two options: module with two FE-I4 (2x4 cm2) for planar sensors or with single FE-I4 (2x2cm2) for 3D sensors
FE-I4 thickness: <350 µm (what is feasible? Prototyping with dummies)
Planar sensors thickness: 200÷300 µm
3D sensor thickness: 230 ± 10 µm (are sensors with array of thin – 10 µm – columns, geometry similar to the FE-I3 tested assemblies)
3D sensor could come with support wafer bonded – how can be removed after bump-deposition?

10. ATLAS sLHC Upgrade
For sLHC, ATLAS foresee a complete replacement of the inner detector:
Replace the Pixel with a 4 or 5 pixel layers: 2 or 3 times the surface
The two internal layers (3xIBL surface) will need material engineering (3D) or new technology (diamond) to sustain radiation fluence (2x1016 neqcm-2)
Time scale:
Prototyping: 2010÷2012
Production: 2013÷2014 (15)
IF 3D Sensors are proven IBL technology, they will find their application in ATLAS & CMS at sLHC.
Two layers of “new technology” pixels
Silicon Pixel Detector

11. Advantage of 3D vs planar
3D sensor has several advantages over planar
More radiation hard: electrode spacing advantageous for charge collection respect to planar
More collected charge – in pixel front-end chips analog/digital crosstalk limits the lowering of threshold
Low bias voltage: 150 V vs >1000 V at high radiation dose
Low power: planar sensor need very low temperature to avoid thermal runaway
There is no Lorentz angle effect
… but the major disadvantage is a new technology
Require proof of production yield
When do we need prototypes for IBL?
FE-I4 will be submitted in March 2010 and prototype back in June
If the design is successful need sensors by mid 2010 (July) and test and irradiation in fall
Is this time schedule compatible with FBK? ….