Planar Pixels Sensors Activitiesin 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 3DDevelopment of specific modelsWork 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 theSi/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

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

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“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. 1067- 1075, Aug. 2005

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 - 30/09/2013 - PPS meeting (LPNHE) 7

Edgeless sensors

Deep trench diffusion(to prevent electricalfield on the damagedcut)

Cut line

Trench definition is critical:- aspect ratio: 20:1- deep etching: 200-230um- trench width: 8-12um

● Goal: make the rim zone equipotential● How: DRIE as for 3D process● Trench doped by diffusion

FBK/LPNHE sensors

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• n-in-p production on FZ, <100> 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

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• 6x30 matrices of FE-I4 pixels shorted together for IV, CV ...

FE-I3

FE-I3

FE-I3

FE-I3

Ω Ω Ω Ω

FE-I4 test structures

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IV of FE-I4 test structures: data vs simulations

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

data (FBK) simulations (LPNHE)

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• 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

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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 adapter Beetle chip

wire-bonding (CERN)

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CCE with stripixels: first test

• First test at CERN with 90Sr (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]

clu

ste

r ch

arg

e (

ke)

cluster charge (ke)

eve

nts

clu

ste

r ch

arg

e (

ke)

strip #

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Irradiations

• Irradiated several test structures (red boxes) of W95 (p-spray @ 3e12/cm2 + p-stop)

– FE-I4 test structures, stripixels, diodes, ...

– goal: study behaviour of edge after irradiation

• n-irradiation @ Ljublijana

– ϕ = 2.5x1015 neq/cm2

• 1st step: IV/CV (VFD, VBD, Ileak..) at low temperature

Interconnectionsin 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.BeauM.BombenG.CalderiniJ.ChauveauG.MarchioriD. LaporteF. CrescioliF. Dematos

L. Bosisio (invited from Univ.Trieste)

A. LounisA. Bassalat (PhD)N. DinuA. FallouE. Gkougkousis (PhD)C. SilviaM.C. Solal

Additional material

• Installation of a 4th 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 5x1015 neqcm-2

• installation originally planned for 2015-2016… advanced (in 2011) to 2013 (Fast-track IBL)

• IBL mounted on new beam pipe• Length: ~64cm • Envelope: Rin = 31mm, Rout=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) = 26880

cells.• 2cm x 2cm!

IBL

Pixel

Planar Slim Edgesensors (CiS)- Oxygenated n-in-n- 200 um thick- guard rings under

pixels - 215um inactive

reg.

3D Slim Edgesensors (FBK +CNM)- p-type- 230 um thick- 200 um inactive

reg.

(Option 1: 100% planar pixel sensors)

Option 2: 75% planar pixel, 25% 3D