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Performance Of Thin Edgeless n -on- p Planar Pixel Sensors for ATLAS Upgrades. A . Bagolini 1 , M. Bomben 2 , M . Boscardin 1 , L. Bosisio 3 , G. Calderini 2,4 , J. Chauveau 2 , G. Giacomini 1 , A. La Rosa 5 , G. Marchiori 2 , N. Zorzi 1
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Performance Of Thin Edgeless n-on-p Planar Pixel Sensors for ATLAS Upgrades A. Bagolini1, M. Bomben2, M. Boscardin1, L. Bosisio3, G. Calderini2,4, J. Chauveau2, G. Giacomini1, A. La Rosa5, G. Marchiori2, N. Zorzi1 1 - Fondazione Bruno Kessler (FBK), Trento, Italy 2- Laboratoirede Physique Nucleaire et de HautesÉnergies (LPNHE), Paris, France 3- Universitàdi Trieste, Dipartimento di Fisica and INFN, Trieste, Italy 4- Dipartimento di Fisica, Università di Pisa, and INFN Sez. di Pisa, Pisa, Italy 5- Section de Physique (DPNC), Université de Genève, Genève, Switzerland 9th “Trento” Workshop on Advanced Silicon Radiation Detectors (3D and p-type Technologies) Genova, February 26th-28th 2014
Edgeless pixels via DRIE • Joint FBK-LPNHE project • Goal: thin, edgeless pixel sensors • Target: intermediate layers • How: make the border a damage free ohmic contact by DRIE • 200 μm thickn-on-pproduction • 500 μm temporary support wafer • Pixel-to-trench distance as low as 100 μm • Main production splits: • p-spray dose • p-stop: present/absent • metal overhang: present/absent • 1 wafer with no DRIE
The active edge project • Goal: HL-LHC ATLAS intermediate pixel layer • n-on-p production • Pixel/trench distance as low as 100 μm Substrate contact Field plate p-stop p-spray n-pixel p-substrate oxide Trench (poly filling) Support wafer oxide
EdgeLess Pixel Test Structures Pixel pitch = 250 mm x 50 mm 2 GR 1 GR No GR
Breakdown studies p-spray dose = 3e12 cm-2 p-spray dose = 5e12 cm-2 Little dependence on trench distance
I-V on FE-I4 sensor Automatic measurement with Temporary metal trench Pads of temporary metal Temporary metal 16
I-V vsp-spray doses p-spray dose = 3e12 cm-2 p-spray dose = 5e12 cm-2 P-spray dose: 5x1012/cm2 • VBD as expected from IV on test structures 8
Irradiation at JSI (Ljubljana) • F: 2.5E15 1-MeV neq /cm2 Measurements on a pad diode I – V log(C) – log(V) α ~ 4.7x10-17 A/cm Results in agreement with literature • Samples were irradiated with reactor neutrons (JSI, Ljubljana) • Limited annealing at room temperature
Interpixel resistance after irradiation p-spray dose = 3x1012/cm2 Excellent pixel isolation even after irradiation
Irradiated FEI4 test structures p-spray dose = 3x1012/cm2 IPAD [A] No GR 1,2,3 GRs
Irradiated FEI4 test structures IGR [A] 3 GRs
trench Temporary metal FE-I4 modules Before temporary metal removal After temporary metal removal after resist patterning • Modules are being assembled at IZM by bump-bonding a few FE-I4 sensors to FE-I4B ROC • Delivery expected by end of November
2 modules assembled for test • sensor S9 400 µm & 10 GRs • sensor S7 200 µm & 3 GRs
400 µm, 10 GRs It was It is
Source scan Disconnected pixels
Conclusions & Outlook • Irradiates structures: OK • FE-I4 two test modules: mixed results • Tackling issues • Next: 10 modules to be assembled • Goal: on beam next autumn