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DEPFET development at the MPI Semiconductor Laboratory

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DEPFET development at the MPI Semiconductor Laboratory. Gerhard Lutz MPI-Semiconductor Laboratory, München Vertex2003 Lake Windermere, Sept.16, 2003. Content. Introduction DEPFET detector-amplifier structure Principle and properties Applications DEFETs as pixel detector - PowerPoint PPT Presentation

Text of DEPFET development at the MPI Semiconductor Laboratory

  • DEPFET development at the MPI Semiconductor Laboratory

    Gerhard LutzMPI-Semiconductor Laboratory, MnchenVertex2003Lake Windermere, Sept.16, 2003

  • ContentIntroduction DEPFET detector-amplifier structurePrinciple and propertiesApplicationsDEFETs as pixel detector In x-ray astronomy (XEUS)In particle colliders (TESLA)DEPFET production in MunichVertex detector for TESLADetector thinning technologyReadout electronicsSummary and conclusions

  • Introduction

    DEPFET detector development at Munich is part of our activities in connection with instute experimentsOwn laboratory is supported by two Max-Planck InstitutesActive in particle physics and astrophysics (X-ray astronomy)Complete semiconductor processing line in houseDetectors mostly based on own conceptsPresent major project: DEPFET pixel detectors

  • The Depleted Field Effect Transistor (DEPFET)Kemmer+Lutz 1985 Device concept: Combination of FET transistor with Sideward depletion (Drift chamber) Gatti + Rehak 1984

  • DEPFET properties

    Field effect transistor on top of fully depleted bulk All charge generated in fully depleted bulk assembles underneath the transistor channel steers the transistor current Combined function of sensor and amplifier low capacitance and low noise Signal charge remains undisturbed by readout repeated readout Complete clearing of signal charge no reset noise Full sensitivity over whole bulk Thin radiation entrance window on backside DEPFET structure and device symbol

  • Operation modes of DEPFET

    DEPFET operation properties Charge collected and stored in internal gate both in transistor on mode and also in transistor off mode Charge is not destroyed by measuring itDEPFET operation modes:Normally on (continuous operation, occasional reset) real time operationNormally off (charge collection in powerless condition) integration mode operation

  • Simulations operation modesReal time mode:Signal collection with DEPFET onReal time signal processing (shaping)Clear internal gate from time to timeDrain currentDrain currentCharge in internal gateApplications:Readout element of drift detectorsor CCDs

  • Simulations operation modesIntegration and Sample mode:Signal collection with turned off DEPFETTurn on DEPFET by gate First current measurementClear internal gateRemeasure current and take difference Drain currentDrain currentCharge in internal gateApplications:Building block of pixel detectors Readout element of drift detectors

  • DEPFET types:MOS-depletionMOS-enhancementJFETOpen (rectangular) geometryClosed (circular) geometry

    DEFET applicationsReadout element ofDrift detectorCCDElement of pixel detector

  • DEPFET 55Fe Spectrum Single DEPFET (JFET, closed geometry)

    At room temperature

    Cooled

  • MPI experiments needing DEPFETsX-ray astronomy: XEUS (next generationEuropean X-ray observatory) successor of XMM-Newton

    Particle physics: TESLA vertex detector

    Both experiments need pixel detectors

  • DEPFET pixel matrix Read filled cells of a row Clear the internal gates of the row Read empty cellsDifference of readings (filled/empty) mesures chargeLow power consumption

    Fast random access to specific array regions

  • Prototype DEPFET-Systemdeveloped with Bonn University 64 x 64 matrix with 50 x 50 m2 pixel designed for Biomedical Applications clock rate : 50 kHz achieved noise in matrix: ~50e64x64 pixel DEPFET-MatrixJFET typeClosed geometry(50x50m2 pixel)low noiseReadout-Chip:CARLOSControl-Chip:Switcher

  • results with prototype systemspatial resolution: ~ 9m(with 50x50 m2 pixel)~ 3.2 mmMatrix-picture with 55Fe:[J.Ulrici, Bonn]Autoradiography with 3H:~ 10 mmdetection of Tritium 3H(5,6keV mean energy)

  • MPI semiconductor laboratory... with modern, custom made facilities ...... for a full 6 silicon process line 800 m cleanroom up to class 1 ...

  • Future X-ray Mission: XEUS (X-ray Evolving Universe Spectroscopy) Experiment Increase in collecting area (factor 100)Increase of collection area (0.5 to 6-30m2)Increase in focal length (7.5 to 50m)Optics and focal imaging on separate satellites Focal detector requirements: faster readout (factor 10 to 100) avoidance of ''out of time'' eventslarger size focal detector (7x7cm2)smaller pixel size (5050m2)Detector requirements can be met with DEPFET pixel detectorsScientific aim: investigation of the universe at an early evolution stage: - early black holes - evolution and clustering of galaxies - evolution of element synthesis6% out of time events in XMM

  • Present DEPFET pixel detector development forXEUS and TESLA Total > 500 MPixel (with 25x25 m Pixelsize)(read out speed 50 MHz)Options:CCDMAPSHAPSDEPFETTESLA vertex detectorThinFastLow powerIn collaboration with Bonn (N.Wermes) and Mannheim (P.Fischer)

    LayerModule size No. Of modulesI13 x 100 mm1 x 8II22 x 125 mm2 x 8III22 x 125 mm2 x 12IV22 x 125 mm2 x 16V22 x 125 mm2 x 20

  • Design of DEPFET pixel detectorsType of DEPFETS:MOS-depletion typeXEUS: zylindrical geometryTESLA: rectangular geometry

    Technology:6 InchDouble-poly, double metal,Self-aligned

  • DEPMOS Technology Simulation DEPMOS pixel array cuts through one cellAlong the channelPerpendicular to the channel Metal 2

    Metal 1

    Oxyd Poly 2 Metal 2 Metal 1 Poly 2 Clear Gclear ChannnelpDeep nn+Deep pPoly 1

  • Pixel prototype production (6 wafer)for XEUS and LC (TESLA)Many test arrays- Circular and linear DEPFETS up to 128 x 128 pixels minimum pixel size about 30 x 30 m - variety of special test structures

    Aim: Select design options for an optimized array operation (no charge loss, high gain, low noise, good clear operation) On base of these results => production of full size sensors

    Structures requiring only one metalization layerProduction up to first metal layer finishedDevices are under testTest results agree very well with device simulations

  • First DEPFET measurements on rectangular test transistors (W = 120m L = 5m)Output characteristics:

    Correct transistor behavior

    Transfer characteristics:

    Device can be completely switched off

    Transistor parameters agree with simulation

  • DEPFET test results: Noise and SpectroscopySingle circular DEPFETL = 5 m, W = 40 mtime-continuous filter, = 6 sec

  • Rectangular double cell test structureas used in TESLA pixel prototype

  • DEPFET test results Clearing of internal gate:complete clearing possible?At which voltage?Single rectangular DEPFET: measure current with cleared internal gateAs function of clear voltage

    Measure pedestal noiseCompare situation of charge generation followed by single clear pulse with many clear pulses before readingSingle clear pulseMany clear pulses

    Messungen

    MessungU PDU out1 hi [V]I lo [A]U out1 lo [V]I hi [A]Delta IBemerkungen

    13-10-1.169.91-6.6083.4373.51Ga 0V

    14-10-3.845.59-10.76139.6494.05Ga 1V

    15-10-3.4841.26-10.76139.6498.38

    16-10-2.9233.70-10.76139.64105.95ohne Terminator

    17-10-2.6830.45-10.8140.18109.73

    18-10-2.6830.45-10.8140.18109.73

    19-10-2.6830.45-10.76139.64109.19

    20-10-2.6029.37-10.44135.32105.95

    21-226.6852.30-1.56163.65111.35Ga 1,5V

    22-227.0846.890.44136.6289.73

    23-229.7211.224.5281.4970.27

    24-226.5254.46-4.12198.24143.78

    25-227.8436.62-4.16198.78162.16

    26-223.6493.380.2139.8746.49

    27-225.1273.380.24139.3365.95

    28-227.4442.030.48136.0894.05

    29-226.9648.510.4137.1688.65

    30-228.3230.140.4137.16107.03

    31-227.5240.950.24139.3398.38

    32-227.5240.950.24139.3398.38

    33-227.6039.870.32138.2498.38

    34-227.6439.330.32138.2498.92

    35-227.6838.780.4137.1698.38

    36-227.5240.950.72132.8491.89

    37-227.5240.950.64133.9292.97

    38-227.6039.871.04128.5188.65

    39-227.6039.870.96129.6089.73

    40-227.9235.540.8131.7696.22

    41-227.6838.780.4137.1698.38

    Clearfrequenz Diagramm

    128.739729729737.9289189189

    117.938918918939.02

    104.259459459538.8540540541

    91.286486486538.8540540541

    81.556756756838.3135135135

    72.097297297338.0432432432

    65.881081081137.9081081081

    61.82702702737.9081081081

    58.718918918937.2324324324

    56.286486486536.9621621622

    48.313513513535.6108108108

    44.238378378434.6437837838

    38.968108108132.887027027

    34.778918918930.9951351351

    31.498378378429.0659459459

    29.336216216228.9308108108

    29.038918918928.7145945946

    28.795675675728.62

    I hi (vor Clearpuls)

    I lo (nach Clearpuls)

    n [Hz]

    I lo [A]

    I in Abhngigkeit von nClear

    Clearfrequenz

    bulkRK/GRGa1Dr1Ga2Dr2Cl loCl hiCl widthCl-G loCl-G hiCl-G widthCl-G delay

    6-50-1-5-3-528100055025

    n [Hz]I PD [A]U out1 hi [V]I lo [A]U out1 lo [V]I hi [A]Delta IBemerkungen

    0.1159.013.9637.93-2.76128.7490.81

    0.2159.023.8839.02-1.96117.9478.92

    0.3134.802.138.85-2.74104.2665.41

    0.4134.802.138.85-1.7891.2952.43

    0.5134.802.1438.31-1.0681.5643.24

    0.6134.802.1638.04-0.3672.1034.05

    0.7134.802.1737.910.165.8827.97

    0.8134.802.1737.910.461.8323.92

    0.9134.802.2237.230.6358.7221.49

    1134.802.2436.960.8156.2919.32

    1.5134.802.3435.611.448.3112.70

    2105.860.2734.64-0.4444.249.59

    3105.860.432.89-0.0538.976.08

    5105.860.5431.000.2634.783.78

    1098.120.1129.07-0.0731.502.43

    5098.120.1228.930.0929.340.41

    10098.120