Performance Of Thin Edgeless n -on- p Planar Pixel Sensors for ATLAS - PowerPoint PPT Presentation

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 1 - Fondazione Bruno Kessler (FBK), Trento, Italy 2- Laboratoire de Physique Nucleaire et de Hautes Énergies (LPNHE), Paris, France 3- Università di 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 26 th -28 th 2014 1

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 thick n-on-p production • 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 2

FEI4 sensors characteristics 3

The active edge project  Goal: HL-LHC ATLAS intermediate pixel layer  n -on- p production  Pixel/trench distance as low as 100 μ m Substrate Field plate contact p -stop n -pixel p -spray p -substrate oxide Trench Support wafer (poly filling) oxide 4

EdgeLess Pixel Test Structures Pixel pitch = 250 m m x 50 m m 2 GR 1 GR No GR 5

Breakdown studies p -spray dose = 3e12 cm-2 p -spray dose = 5e12 cm-2 Little dependence on trench distance 6

I-V on FE-I4 sensor Automatic measurement with Temporary metal trench Pads of temporary metal Temporary metal 7 16

I-V vs p -spray doses p -spray dose = 3e12 cm-2 p -spray dose = 5e12 cm-2 P-spray dose: 5x1012/cm2  V BD as expected from IV on test structures 8 8

Irradiation at JSI (Ljubljana) F : 2.5E15 1-MeV n eq /cm 2 • Samples were irradiated with reactor neutrons (JSI, Ljubljana) – Limited annealing at room temperature Measurements on a pad diode I – V log(C) – log(V) α ~ 4.7x10 -17 A/cm Results in agreement with literature 9

Interpixel resistance after irradiation p-spray dose = 3x10 12 /cm 2 Excellent pixel isolation even after irradiation 10

Irradiated FEI4 test structures p-spray dose = 3x10 12 /cm 2 I PAD [A] No GR 1,2,3 GRs 11

Irradiated FEI4 test structures I GR [A] 3 GRs 12

FE-I4 modules trench Temporary metal 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 13

2 modules assembled for test  sensor S9  400 µm & 10 GRs  sensor S7  200 µm & 3 GRs 14

400 µm, 10 GRs It is It was 15

Source scan Disconnected pixels 16

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 17