Planar Pixels Sensors Activities in France

Phase-2 and core R&D activities in France -Development of sensor simulations models -Sensor technology Edgeless/active edge sensors Reduced thickness - R&D on interconnections - Test beam activities (M. Bomben ATLAS PPS testbeam coordinator)

Device simulations Device simulations (Silvaco) General expertise in Silvaco 2D and 3D Development of specific models Work to extend to n-in-p sensors the model of interface defect traps developed for n-in-n devices Insertion of intermediate levels in the gap to reproduce the Si/SiO2 interface defects. After radiation and better describe the leakage current and breakdown behavior

Good agreement with measurements on our n-in-p device production

5 Silvaco 3D used to calculate the Ramo potential for the digitizer of present ATLAS n-in-n pixel

6 “Simulation of Heavily Irradiated Silicon Pixel Sensors and Comparison with Test Beam Measurements” V. Chiochia et al., Nuclear Science, IEEE Transactions on, vol.52, no.4, pp , Aug Activation energies as in EVL model Since the present pixel detector is n-in-n bulk, Chiochia model instead of Pennicard used for radiation damage (Silvaco 3D)

Simulation vs Chiochia 2005 results M. Bomben - TCAD Simulations - 30/09/ PPS meeting (LPNHE) 7

Edgeless sensors Deep trench diffusion (to prevent electrical field on the damaged cut) Cut line Trench definition is critical: - aspect ratio: 20:1 - deep etching: um - trench width: 8-12um ● Goal: make the rim zone equipotential ● How: DRIE as for 3D process ● Trench doped by diffusion FBK/LPNHE sensors

10 n-in-p production on FZ, Si 200 μm thick sensors produced in FBK cleanroom – 500 μm thick support wafer (bonded by Sintef) pixel-to-trench distance as low as 100 μm aiming at intermediate pixel layer ~20 wafers produced different p-spray dose (low/high) p-stop present/absent Nucl. Instrum. Meth. Phys. Res. Sect. A 712, 41 (2013) FBK/LPNHE active-edge sensor production

11 6x30 matrices of FE-I4 pixels shorted together for IV, CV... FE-I3 ΩΩΩΩ FE-I4 test structures

12 IV of FE-I4 test structures: data vs simulations BD from guard ring current vs V bias (innermost GR at ground like pad) data: from FE-I4 test structure (matrix). simulation: 2D-sim of edge pixel V BD (>100V) increases with #GR as expected. Larger than V depl ~30 V agreement on V BD between data and simulation within 20% or better data (FBK) simulations (LPNHE)

13 long-as-strip, wide-as-pixel sensors can be wire-bonded to read-out chip => no need for bump-bonding “illuminating” (laser/MIPs) the edge region, CCE at the periphery can be studied Stripixels for CCE measurements

14 Stripixels for CCE measurements goal: compare CCE before/after irradiation – with MIPs or laser HV: wire-bonding to bias-tab read-out system: stripixel wire-bonded to pitch adapter of Beetle chip; read-out through Alibava system (1 at LPNHE, 1 in Geneva/CERN) HV distribution 3 stripixel sensors with different layout pitch adapterBeetle chip wire-bonding (CERN)

15 CCE with stripixels: first test First test at CERN with 90 Sr (trigger with scintillator beyond stripixels) Stripixels DC coupled to the Beetle chip Results not fully understood; measurement to be redone with decoupling pitch adapter time [ns] cluster charge (ke) events cluster charge (ke) strip #

16 Irradiations Irradiated several test structures (red boxes) of W95 3e12/cm2 + p-stop) – FE-I4 test structures, stripixels, diodes,... – goal: study behaviour of edge after irradiation Ljublijana – ϕ = 2.5x10 15 n eq/ cm 2 1st step: IV/CV (V FD, V BD, I leak..) at low temperature

Interconnections in the framework of AIDA

Further R&D (2014-) Interest in microchanneling (BaBar heritage, now ALICE, LHCb) Study of micro-machined substrates for cooling

Persons involved in planar pixels sensors T.Beau M.Bomben G.Calderini J.Chauveau G.Marchiori D. Laporte F. Crescioli F. Dematos L. Bosisio(invited from Univ.Trieste) A. Lounis A. Bassalat (PhD) N. Dinu A. Fallou E. Gkougkousis (PhD) C. Silvia M.C. Solal

Additional material

Installation of a 4 th pixel layer inside the current pixel detector: performance of current pixel detector will degrade before main tracker upgrade (Phase 2) maintain physics performance in high occupancy environment (higher granularity, r/o bandwidth) increase radiation hardness (IBL fluence ~ 5x B-Layer fluence)  Insertable B-Layer 250 Mrad TID and 5x10 15 n eq cm -2 installation originally planned for … advanced (in 2011) to 2013 (Fast-track IBL) IBL mounted on new beam pipe Length: ~64cm Envelope: R in = 31mm, R out =40mm 14 staves, 32 pixel sensors / stave. Front-end chip: FE-I4 (IBM 130 nm CMOS tech.) 50μm x 250μm 80(col) x 336 (rows) = cells. 2cm x 2cm!

Planar Slim Edge sensors (CiS) - Oxygenated n-in-n um thick - guard rings under pixels - 215um inactive reg. 3D Slim Edge sensors (FBK +CNM) - p-type um thick um inactive reg. (Option 1: 100% planar pixel sensors) Option 2: 75% planar pixel, 25% 3D