ATLAS HVCMOS R&D Collaboration

Ristic, B.

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Branislav RistićCERN / Université de GenèveOn behalf of the ATLAS HVCMOS R&D CollaborationActive pixel sensors in ams H18/H35 HV-CMOS technology for the ATLAS HL-LHC upgrade10th International "Hiroshima" Symposium Xi'an, Chinav1.126/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 2LHC Upgrade● LHC upgrade to higher luminosities planned for 202x ● Integrated luminosity: 300 fb-1  → 3000 fb-1 ● Hybrid detectors proven to be rad-hard enough● Main drawback: Price● Bump bonding expensive due to special processes● Sensor processes non-standard + on small wafers● ITk requires ~100-200m2 of silicon  price matters→26/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 3LHC Upgrade● LHC upgrade to higher luminosities planned for 202x ● Integrated luminosity: 300 fb-1  → 3000 fb-1 ● Hybrid detectors proven to be rad-hard enough● Main drawback: Price● Bump bonding expensive due to special processes● Sensor processes non-standard + on small wafers● ITk requires ~100-200m2 of silicon  price matters→ → Possible solution: Industrialized processes● … and interconnection technologies● Commercially available by variety of foundries– Large volumes,  multiple vendors● 8” to 12” wafers– Low cost per area, wafer thinning quite standard● usually p-type Cz silicon– Thin active layer, helpful to disentangle tracks in boosted jets and at high eta● Requires low capacitance  small pixels→26/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 4HV-CMOS sensors in ams technologyAustria Micro Systems offers HV-CMOS processes with 180nm and 350nm feature size ● Several substrate resistivities O(10 - 1000)Ωcm   N→ eff > 1011...1014/cm3● Collecting electrode and HV isolation  Deep N-Well →● Biasing of substrate to ~60-100V(H18) ~150V (H35) ● Depletion depth theoretically in the order of 10  - 100µm  Drift signal ~500...O(1000)e→ -● On-sensor amplification possible - and necessary for good S/N● Key: small pixel sizes  low capacitance  low noise→ →● Additional circuits, e.g. discriminator● Adjustable high output signal● Capacitive coupling (CCPDs)● Sub-pixel encoding (small pixels)● Hybridization by gluing using flip chip machines● Glue thicknesses of several μm reached● Below 1 μm precise alignmentDeep N-wellPMOSNMOSDepletedP-substrate Not depleted26/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 5A short story of ams CCPDs for ATLAS   ams H352012:    H18CCPDv12013:  H18CCPDv2    2013:  H18CCPDv3    2014:  H18CCPDv4    2013: H35CCPDv1      2015: H35CCPDv2         ams H182015/16: Demonstrator● Proof of principle● Standard lib components  → Non radiation hard● Chessboard structure● Radiation hardened design - Circular transistors● Several pixel flavours● Irradiated to 830MRad    and 1x1016neqcm-2 ● CLICpix focused● New amplifiers● One diode w/o electronics    directly accessible● Lower noise amplifiers● New pixel type STime:  - time encoding● Linear sub pixel arrangement● Analogue pixels ● Timewalk compensating  discriminators● Optimization towards higher   bias voltage stability  → see Zhijun Liang's posterStriplikeSensors● Timewalk compensating    discriminators● HV optimizations● Purely analogue   (no discriminators)● Two pixel types containing  one or two stage amplifiers● Submission on the way● More information laterThe HV2FEI4 CCPD familyIdea and most designs by Ivan Peric2015:  H18CCPDv5          H18Demo26/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 6Irradiation of H18CCPDv4 samplesX-Ray irradiation up to 1000MRad (158.4MRad/day): stand alone CCPD V4, powered ● Increase of leakage current after 400 MRad● Drops to 380 nA after 26 days of annealing at room temperature → High temperature annealing not necessary● Amplifier with linear and circular feed back transistor investigated● Linear FB transistor shows noise after 100MRad● Circular FB transistor remains quiet up to 1GRad  Fe-55 peak clearly visible→Fe-55 after 1GRad (HV=-60V)SNR after 1GRad = 26.5CPPM26/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 7Irradiation of H18CCPDv4 samples0 100 200 300 400 500 600050100150200250300350400Amplitude of 1V injection versus doseCCPD_AMS_V4LIN Col 2 – Row 1ELT Col 20 – Row 1Dose (MRad)Amplitude (mV1000lin. FB transistorcirc. FB transistorAfter retuningAmplifier output vs. X-Ray doseAfter 25d annealing @RTlin. FB transistorcirc. FB transistorAmplifier output vs. proton doseX-Ray irradiation up to 1000MRad: stand alone CCPD V4, powered ● Amplifier output signal recovered by annealing at room temperature and retuning● Relative amplitude of linear FB transistor: 88%, but noisy● Relative amplitude of cicrular FB transistor: 62%Proton irradiation up to 560MRad:stand alone CCPD V4, powered● No annealing or retuning performed● Relative amplitude of linear FB transistor: 75%, but noisy● Relative amplitude of cicrular FB transistor: 63%● Investigation ongoingCPPM26/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 8Testbeam results on H18CCPDv4 samples● Multiple testbeam periods during last 1.5 years● Performed using new FEI4 based telescope● Resolution at DUT ~8/12um for typical telescope configuration ● Two H18CCPDv4 samples tested● 402: unirradiated  and  404: 1x1015neqcm-2● Subpixel encoding not tested  FE-I4 pixel pairs merged→● High efficiency of 99.7% before and 96.2% after irradiationDUTTelescope PlanesX position [µm]Y position [µm]“SAmp“ pixels: untunedReconstruction artefactMergedpixel26/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 9Bias and threshold Scans● Bias scan from 0V to breakdown voltage performed● Diffusion contributes significantly to signal in unirradiated case● Early breakdown prevented optimal performance (especially in case of irradiated sample)● H18v4 samples can be biased up to ~95V  New data expected this year→● Threshold scan from close to the noise edge to up to several thousand electrons performed● Detection efficiency depends highly on properly tuned sample (if not biased with high voltages)26/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 10Timing comparison● Output signal shows broad timing distribution of several bunch crossings● Slow signal/tail suppressed after irradiation hinting on trapping of diffusion component ● Improvement of timing can be reached by higher bias voltages  higher drift fraction of signal→● ATLAS requires signal generation in one bunch crossing   Time walk compensation in H18v5→#HitsLog scale!26/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 11(Edge) Transient Current TechniqueTCT (Transient Current Technique): record time-resolved charge collection● Charges usually generated via infrared laser, shot into the bulk of sensor● Constant charge deposition per pulse  averaging over many pulses cancels noise→● Observables: Transient current (charge movement)Integrals (collected charge)● Fast signals (~ns)  External amplification, fast readout with scopes→● Edge TCT: shooting in through the side-wall of the sensor with a IR laser● Can study the charge collection at different depths  depletion?→Why E-TCT?● Expected depletion depth for 10 Ohm*cm around 10 µm  500-600e for a MIP→● Observed: ~1500-1900 e- (~1200 e- after irradiation) from in-pixel charge-sensitive amplifiers● Origin of discrepancy unclearChristian GallrappCERN / PH-DT-DD26/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 12E-TCT on ams samplesMeasurements on H18CCPDv3 samples● 10Ωcm substrate, max. ~90V bias● One dedicated passive 100 x 100 µm2 diode accessible● No neigbours  possible edge effects→● Irradiation at CERN PS (Irrad 1) without biasing● Fluences: 2.3, 6 and 11.1x1015 p/cm2 (1.42, 3.72 and 6.9x1015 neq/cm2 )● p-irradiated samples cooled to 0 degrees for measurement● Irradiation at JSI Ljubljana, Slovenia● Fluences: 1, 7, 20x1015 neq/cm2● Collected charge obtained as integral over 5ns Measurements on H35 samples (CHESS1)● 20Ωcm substrate, max. 120V bias● 100 x 45 µm2 diodes forming an array accessible● Irradiation at JSI Ljubljana, Slovenia● Fluences: 0.2, 0.5, 1, 2, 5, 10x1015 neq/cm2● Collected charge obtained as integral over 25ns (!)a.u.26/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 13E-TCT results of ams H18 Samples● Relative charge collection (CC) after neutron irradiation● CC at 0V after 1x1015 neq/cm2 near 0  Diffusion component degraded by trapping→● Can be recovered to 85% even after 2x1016 neq/cm2● Collected charge doubled in case of 7x1015 neq/cm2  Acceptor removal effect  Deeper depletion zone→ →● ….and after proton irradiation● CC exceeds unirradiated case at below 10V● Largest collection after 1.42x1015 neq/cm2 (p irradiation) reaches relative CC of up to 6 at 80V  Acceptor removal for protons much stronger than for neutrons at that fluence→● Comparable after 7x1015 neq/cm2: 1.9 (n) vs. 2.2 (p) at 80Vneutron irradiatedPreliminaryproton irradiatedCERN / PH-DT-DDUniversité de Genève26/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 14Depletion depth on H18 and H35 samples● Depletion depths obtained as FWHM of scanning over y● H18 and H35 samples yield comparable results● 1x1015 neq/cm2 inconclusive: Precise knowledge of fluence crucial● Results confirm charge collection measurements● Discrepancy between proton and neutron irradiation● Equal charge collection for ~7x1015 neq/cm2Chip surfaceScan directiona.u.Bias = 80VCERN / P H-DT-DDUniversi té de Ge nèveJSI Ljubl janaPreliminaryPreliminaryH18CCPDv3 CHESS1Presented  at the IT K Week Sep 2015  by Igor Mandic26/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 15The AMS H35 Demonstrator● Engineering run, proving feasibility of full reticle size sensors● Built in AMS H35 350nm HV-CMOS process● Substrate resistivities: 20, 80, 200, 1000Ωcm● Submission on-goingFloorplan● Analog pixels (only amplifiers) for FEI4 coupling● 3  flavours optimized for gain and/or speed● Standalone NMOS matrix● Different in-pixel amplifiers and discriminators● Read out by FE-I4 or an FE-I3 like digital structure at periphery● Standalone CMOS matrix● Different in-pixel amplifiers● Can be read out by FE-I4● CMOS discriminators at periphery and FE-I3 like digital structure at peripheryStandalone NMOS matrix16 rows x 300 columnsAnalog matrix16 rows x 300 columnsAnalog matrix16 rows x 300 columnsStandalone CMOS matrix16 rows x 300 columnsIFAE     |     KITUniversity of Liverpool26/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 16The AMS H35 Demonstrator● Timewalk has been addressed by a timewalk compensating discriminator● Post design simulation reveals significant improvement especially for low charges● Higher substrate resistivities will yield higher signals, further mitigating this issue● Possible backside implant for HV biasing  homogenious E-field through bulk→0.5 MIPs3 MIPs~25 ns50 1750.5 MIPs3 MIPsfew ns420 500IFAE     |     KITUniversity of Liverpool26/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 17Summary and outlook● HV-CMOS sensors are promising sensor candidates for the upgrade of the ATLAS Inner Tracker● Very good detection performance and radiation hardness● Cost efficient (standard processes and gluing instead of bump bonding)● Offered by various vendors and in big volumes● Testbeam measurements yield detection efficiencies of up to 99.7% for irradiated and 96.2% for 1x1015neqcm-2 irradiated samples under non-optimal conditions● Deteorioration of Amplifier signals after irradiation with ionizing particles can be mitigated by room temperature annealing and retuning● Timewalk issue has been identified and addressed by improved comparator design● Edge TCT measurements show improved charge collection for irradiated sensors due to the acceptor removal effect● Up to 6 times (2 times for neutron irradiation) the initial charge collected for 1...2x1015neqcm-2● Full size demonstrator design in H35 technology prepared● Production on several (high) bulk resistivities for improved SNR● Back side metallization by ams possible● Mu3e tracker will be built as HV-CMOS MAPS  Implementation for ATLAS conceivable →26/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 18Backup26/08/15 Branislav Ristic - HSTD10, Sep 2015, Xi'an, China 19-120V -120V3.3V  HV Biasing - bulk resistivity and contact positionLow resistivity (20 Ohm*cm) High resistivity (1 kOhm*cm)Back Side bias Top Side biasE-Field Lines - High resistivity (1 kOhm*cm)E-Field distribution - Top Side bias

Active pixel sensors in ams H18/H35 HV-CMOS technology for the ATLAS HL-LHC upgrade

https://publikationen.bibliothek.kit.edu/230103828/3817017

Active pixel sensors in ams H18/H35 HV-CMOS technology for the ATLAS HL-LHC upgrade

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