CMOS Monolithic Active Pixel Sensors

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1 CMOS Monolithic Active Pixel Sensors A tool to measure open charm particles M. Deveaux Goethe-Universität Frankfurt/M

2 Sherlock Holmes and Mystery of the Soup or How to build a webcam based carrot detector M. Deveaux Goethe-Universität Frankfurt/M

3 A Question to Sherlock Holmes M. Deveaux, FAIRNESS Workshop, Sept 2012, Hersonissos, Greece 3 Prof. Dr. Johanna Wanka, Federal Minister of Research, Germany The soup The cook

4 Sherlock Holmes Quest M. Deveaux, FAIRNESS Workshop, Sept 2012, Hersonissos, Greece 4 How can one check that the soup has cooked?

5 Sherlock Holmes Quest M. Deveaux, FAIRNESS Workshop, Sept 2012, Hersonissos, Greece 5?

6 Sherlock Holmes Quest M. Deveaux, FAIRNESS Workshop, Sept 2012, Hersonissos, Greece 6

7 Sherlock Holmes Quest = M. Deveaux, FAIRNESS Workshop, Sept 2012, Hersonissos, Greece 7

8 Sherlock Holmes Quest Dissolves fast Gets quickly soft if cooked Gets slowly soft if cooked M. Deveaux, FAIRNESS Workshop, Sept 2012, Hersonissos, Greece 8

9 Sherlock Holmes Quest Lets test ingredients, which keep information on the cooking process. M. Deveaux, FAIRNESS Workshop, Sept 2012, Hersonissos, Greece 9

10 Sherlock Holmes Quest Dissolves also at room temperature Keeps softening after cooking Reacts slowly, might overlook cooking M. Deveaux, FAIRNESS Workshop, Sept 2012, Hersonissos, Greece 10

11 Sherlock Holmes Quest The Quest of modern heavy ion experiments We will have to test as many ingredients as possible to obtain a conclusive answer. CBM 11

12 What means soup: Hadronic Matter M. Deveaux 12

13 What means carrot: Observables 13 UrQMD transport calculation U+U 23 AGeV

14 I. Vassiliev, C. Dritsa My topic today How can this technology help to find this D 0 (cū) K - (ūs) π + (uđ) in this! Cent. AuAu coll. at 25 AGeV 160 p K + 13 K - ct = 123 µm UrQMD + GEANT4 M. Deveaux 14

15 Why webcams? M. Deveaux 15

16 Why webcams M. Deveaux 16 Add metall foil to deflect light A little radioactivity (Am-241, 60 kev photons work fine)

17 Why webcams? M. Deveaux 17

18 How does a webcam work? M. Deveaux V Reset +3.3V Output SiO 2 SiO 2 SiO 2 N++ N++ N+ P+ 50µm 15µm P- P+

19 The pre-amplifyer M. Deveaux 19 Amplifier (Source Follower) Layout of a classical Active Pixel (simplified)

20 Operation principle of the pre-amplifyer M. Deveaux 20 Reset Water = positive charge MIP-man Level indicator (Charge-voltageconverter) Photodiodetap Pixelcapacitorbasin Readoutelectronikman

21 Operation principle of the pre-amplifyer M. Deveaux 21 Readout cycle in three steps: First step: Readout-electronic-Man gives a Reset At a photodiode, once observes a leakage current. When the basin is fully recharged, the water level is noted for reference.

22 Operation principle of the pre-amplifyer M. Deveaux 22 Second step: Readout-elektronic-man has care for his other pixels now Sometimes MIP-man passes by to take bucket of positiv charge (electrons are collected by the diode after a hit).

23 The operation principle of the pre-amplifyer M. Deveaux 23 Third step: Readout-elektronik-man returns to check the water-level in the basin.??? The level has dropped => MIP-man must have passed by. MAPS pixels may measure even if they are disconnected from readout electronics and power supply.

24 Some sources of uncertainty M. Deveaux 24 Shot noise: Number of fallen drops fluctuates over time. Noise Gain of the indicator is different for each pixel

25 Relation between model and schematics M. Deveaux 25

26 Readout system of early MAPS M. Deveaux 26 Architecture of MIMOSA I X- and Y-shift registers to select pixels. IO-Signals needed: Common Amplifier Clock, Reset, Synchro and analogue output

27 Comparing pixel sizes M. Deveaux 27 Maps-pixel (25 x 25 µm²) State of the art hybrid pixel (100µm x 120 µm) Hybrid pixel Hybrid pixel Hybrid pixel

28 MAPS: The operation principle M. Deveaux V Reset +3.3V Output SiO 2 SiO 2 SiO 2 N++ N++ N+ P+ 50µm 15µm P- P+

29 The meaning of thin M. Deveaux 29 Size: 21.2 x 10.6 mm 2 Bending radius: ~30 cm 50 µm thickness Bended due to inner tensions Flexible silicon!

Open charm reconstruction: Concept Target (Gold) z Detector2 Detector 1 Primary Beam: 25 AGeV Au Ions (up to 10 9 /s) Reconstructing open charm requires: Excellent secondary vertex resolution (~ 50

30 Open charm reconstruction: Concept Target (Gold) z Detector2 Detector 1 Primary Beam: 25 AGeV Au Ions (up to 10 9 /s) Reconstructing open charm requires: Excellent secondary vertex resolution (~ 50 µm) => Excellent spatial resolution (~5 µm) => Very low material budget (few 0.1 % X 0 ) => Detectors in vacuum Primary vertex Short lived particle D 0 (ct = ~ 120 µm) Secondary vertex A good time resolution to distinguish the individual collisions (few 10 µs) Reconstruction concept for open Very charm good radiation tolerance (>10 13 n eq /cm²) Central Au + Au collision (25 AGeV) M. Deveaux, 30

point res. [µm] ~ 5 ~ 30 Material budget [ X 0 ] ~ 0.

31 Established pixel detector technologies (2003) M.Deveaux 31 NA60 hybrid pixel Required (CBM) Hybrid pixels Single point res. [µm] ~ 5 ~ 30 Material budget [ X 0 ] ~ 0.3% 1% Time resolution [µs] few Rad. hardness [n/cm²] > >> CCD ~ 5 ~0.1% ~100 << 10 10

32 Requirements vs. detector performances (2003) M. Deveaux 32 More sensitivity We need both More statistics NA60 hybrid pixel Required Hybrid pixels Single point res. [µm] ~ 5 ~ 30 Material budget [ X 0 ] ~ 0.3% ~ 1% Time resolution [µs] few Rad. hardness [n/cm²] > >> CCD ~ 5 ~ 0.1% ~100 << 10 10

33 Performances of MAPS (2003) MAPS provide an unique compromise between: sensitivity high rate capability Required Hybrid pixels Single point res. [µm] ~ 5 ~ 30 Material budget [ X 0 ] ~ 0.3% 1% Time resolution [µs] few Rad. hardness [n/cm²] > >> *Sensor only CCD ~ 5 ~0.1%* ~100 << MAPS** (2011) 3.5 ~0.05%* ~10000 > **Best of all prototypes 33

34 M. Deveaux 34 Easy, isn t it? X 0? n eq /cm²???

35 X 0 and multiple scattering Definition of the radiation length (X 0 ): Distance in a material, which decelerates charged particles with to 1/e of its energy. Material constant, tables available at Relevance of the radiation length (X 0 ): Uncertainty range x 1) The thinner, the better. 2) 1% X 0 = 1mm silicon M. Deveaux 35

36 NIEL - Factor [n eq ] What means n eq /cm²? 36 Relative non ionising dose of neutrons and pions 2,0 1,5 Neutrons Pions 1,0 0,5 0,0 Data from: A. Vasilescu and G. Lindstroem, Displacement damage in Silicon on-line compilation: 0, E [MeV] kin

37 Radiation tolerance 37

by charged particles and photons Non-ionising radiation: Energy deposited into the crystal lattice Atoms get displaced

38 What about radiation hardness? M. Deveaux 38 Ionising radiation: Energy deposited into the electron cloud May ionise atoms and destroy molecules Caused by charged particles and photons Non-ionising radiation: Energy deposited into the crystal lattice Atoms get displaced Caused by heavy (fast leptons, hadrons) charged and neutral particles Farnan I, HM Cho, WJ Weber, "Quantification of Actinide α-radiation Damage in Minerals and Ceramics." Nature 445(7124):

39 39 Sensor R&D: Tolerance to non-ionising radiation +3.3V Output +3.3V GND SiO GND 2 SiO 2 SiO 2 N+ SiO 2 P++ P++ N++ P++

40 Sensor R&D: Tolerance to non-ionising radiation +3.3V Output +3.3V GND SiO GND 2 SiO 2 SiO 2 N+ SiO 2 P++ P++ N++ P++ Key observation: Signal amplitude is reduced by bulk damage 40

41 Sensor R&D: Tolerance to non-ionising radiation +3.3V Output +3.3V GND SiO GND 2 SiO 2 SiO 2 N+ SiO 2 P++ P++ N++ P++ E Electric field increases the radiation hardness of the sensor Draw back: Need CMOS-processes with low doping epitaxial layer 41

42 D. Doering, P. Scharrer, M. Domachowski M. Deveaux 42 S/N of MIMOSA-18 AHR (high resistivity epi-layer) Signal to Noise (Ru-106 ) T=-34 C/-70 C 0.2 x n eq /cm² 10µm 12.5µm 25µm Radiation dose [10 13 n eq /cm 2 ] Mimosa-9 (2005) 20 µm standard epi Safe operation Sensor design: PICSEL Group, IPHC Strasbourg, et al. Sensor test and plots: AG Stroth, IKF Frankfurt/M Plausible conclusion: Radiation tolerance ~10 14 n eq /cm² reached Cooling required to operate heavily irradiated sensors

43 Noise [e] Radiation damage Noise and cooling Temperature [ C] Unirradiated n eq /cm n eq /cm 2 t Int = 4 ms (slow) -34 Sensor design: PICSEL Group, IPHC Strasbourg, et al. Sensor test and plots: AG Stroth, IKF Frankfurt/M Cooling is needed to exploid the improved radiation tolerance Alternative solution: Fast integration times help M. Deveaux 43

44 Performances of MAPS Required Hybrid pixels Single point res. [µm] ~ 5 ~ 30 Material budget [ X 0 ] ~ 0.3% 1% Time resolution [µs] few Rad. hardness [n/cm²] > >> *Sensor only CCD ~ 5 ~0.1%* ~100 << MAPS** (2011) 3.5 ~0.05%* ~10000 > **Best of all prototypes Sensor design: PICSEL Group, IPHC Strasbourg, et al. Sensor test and plots: AG Stroth, IKF Frankfurt/M 44

45 Performances of MAPS Required Hybrid pixels Single point res. [µm] ~ 5 ~ 30 Material budget [ X 0 ] ~ 0.3% 1% Time resolution [µs] few Rad. hardness [n/cm²] > >> *Sensor only CCD ~ 5 ~0.1%* ~100 << MAPS** (2011) 3.5 ~0.05%* ~10000 ~ **Best of all prototypes Sensor design: PICSEL Group, IPHC Strasbourg, et al. Sensor test and plots: AG Stroth, IKF Frankfurt/M 45

46 Sensor Sensor R&D: How to gain speed External ADC Offline Cluster finding Output Add pedestal correction ~1000 discriminators On - chip cluster-finding processor Output: Cluster information (zero surpressed) MAPS are built in CMOS technology Allows to integrate: sensor analog circuits digital circuits on one chip. 46

47 Pixel with pedestal correction ~1000 discriminators Sensor R&D: How to gain speed Serial readout MIMOSA-1 (2000) MIMOSA-5 (2002) MIMOSA-20 (2006) MIMOSA-26 (2009) Readout Serial Serial Serial Mk. 2 Digital Pixel/line/s 5M 20M 50M 2500M Data/sensor: 1200 Mbps parallel 160 Mbps Readout time before: 1-20 ms Readout time now: ~100 µs Sensor design: PICSEL Group, IPHC Strasbourg, et al. On - chip cluster-finding processor Output: Cluster information (zero surpressed) Improve further with shorter columns. 47

48 Performances of MAPS Required Hybrid pixels Single point res. [µm] ~ 5 ~ 30 Material budget [ X 0 ] ~ 0.3% 1% Time resolution [µs] few Rad. hardness [n/cm²] > >> *Sensor only CCD ~ 5 ~0.1%* ~100 << MAPS** (2011) 3.5 ~0.05%* ~10000 ~ **Best of all prototypes 48

49 Performances of MAPS Required Hybrid pixels Single point res. [µm] ~ 5 ~ 30 Material budget [ X 0 ] ~ 0.3% 1% Time resolution [µs] few Rad. hardness [n/cm²] > >> *Sensor only CCD ~ 5 ~0.1%* ~100 << MAPS** (2011) 3.5 ~0.05%* ~ **Best of all prototypes 49

50 Applications of MAPS 50 STAR HFT ALICE ITS? EUDet Telescope CBM MVD ILC?

51 Need for Speed II: A new generation at the horizon PMOS Transistor Reset +3.3V +3.3V Output SiO 2 SiO 2 SiO 2 P N++ N+ P N++ N+ P+ 50µm 15µm P- P+ In standard CMOS sensors, no PMOS transistors are possible in pixel => No high level functions like discriminators => slow M. Deveaux 51

52 Going beyond rolling shutter 52 Advanced CMOS Standard CMOS Separate sensor and electronics on chip SOI Sensors 3D VLSI integration

53 50µm +3.3V Advanced CMOS Reset +3.3V Output SiO 2 SiO 2 SiO 2 N++ P N++ P N+ deep P-well 15µm N+ P+ Full CMOS is reached in modern 0.18µm processes with quad-well Exploited for IPHC AROM sensors (discriminator on pixel) + Simple, cost efficient, widely available in industry + Industrial trend toward better epitaxial layers - On pixel electronics limited by pixel surface P- P+ M. Deveaux 53 Players among others: PICSEL Group, IPHC Strasbourg, et al.

54 SOI - Pixels M. Deveaux 54

55 SOI - Pixels + Dedicated sensor silicon + dedicated electronics silicon + Conceptually more radiation tolerance possible - Thick BOX Oxide may be vulnerable to radiation damage - Still under early R&D, moderate industrial support M. Deveaux 55

56 Latest news (Yasuo Arai, Vertex 2013) M. Deveaux 56 Electronics Current shield E-Field shield Current shield Active volume

57 M. Deveaux 57 3D VLSI integration, the best of all worlds Players among others: Fermilab, ÁIDA Collaboration Individual chips form always a compromise. 3D VLSI integration aims to pile chips and to connect them Potential: Get the best of all worlds

58 How to put chips together (simplified) Players among others: Fermilab, ÁIDA Collaboration Drill holes (via) deep into the chips and fill with metal Thin silicon until vias are seen on back side Add bond pads on the back side Bond chips M. Deveaux 58

a) Don t take industry by the letter b) Use bigger through vias to ease alignment while bonding Future submissions should be much

59 Status: (Ray Yarema, VERTEX2013) Prototypes submitted by large community, coordinated by Fermilab Industry failed with bonding => Years of delays and desasters Finally, few months ago: First individual working devices delivered and tested Problems are understood: a) Don t take industry by the letter b) Use bigger through vias to ease alignment while bonding Future submissions should be much easier Ray Yarema: In hindsight,, we might have saved ~ 2 years and avoided a lot of grief. That s why it is called research. M. Deveaux 59

60 The final question: How to do system integration M. Deveaux 60 Again, this structure will be fixed with the novel Anti Gravitation Glue.

61 Outlook: The story has just started Idea from R. De Oliveira, W.Dulinski SERNWIETE (mechanical demonstrator) A bended MIMOSA-26 in a foil

62 Outlook: The story has just started Idea from R. De Oliveira, W.Dulinski My collaborators: SERNWIETE (mechanical demonstrator) A bended MIMOSA-26 in a foil PICSEL group, IPHC Strasbourg AG Prof. Stroth, Goethe University Frankfurt What else should have been mentioned: I. Peric, ZITI, Heidelberg Partially depleted 2.5D MAPS V. Re et al, INFN, Pavia, Bergamo MAPS with discriminator/shaper ând many others

Development of CMOS pixel sensors for tracking and vertexing in high energy physics experiments

PICSEL group Development of CMOS pixel sensors for tracking and vertexing in high energy physics experiments Serhiy Senyukov (IPHC-CNRS Strasbourg) on behalf of the PICSEL group 7th October 2013 IPRD13,