Preliminary Results of the CiS-HH SRD...

download Preliminary Results of the CiS-HH SRD Projectssd-rd.web.cern.ch/ssd-rd/rd/talks/lindstroem-CIS-rd-2001.pdfGunnar Lindstrm, CiS report, CERN 29-Nov-01 Wacker 111 ρ = 2 Œ 5 kΩcm,

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  • Gunnar Lindstrm, CiS report, CERN 29-Nov-01

    Optimization of DOFZ for manufacturing process Cost effectiveness, how much [O] is enough? vs. , influence on surface properties Hidden parameters affecting radiation hardness

    (example: HCl vs. TCA) Czochralski silicon, a possible alternative?

    Material: FZ: Wacker, Cz: Sumitomo

    Processing: CiS Erfurt, process very similar to ATLAS wedge Test diodes multi g.r.(HH) + test fields(Dortmund)

    Material characterization:IR: ITME Warsaw, B. SurmaSIMS: SIMS Lab Warsaw, A. Barcz4-point probe and management: ITME, E. NossarzewskaDLTS, C/V + I/V: Uni-HH

    Radiation damage studies (Uni-HH):Irradiations with p (PS-CERN), n (TRIGA-Ljubljana),Co-60 Gamma (BNL, collab. with Z. Li, E. Verbitskaja)Tools: DLTS + Laplace-DLTS, TSC, TCT, C/V + I/V-annealing, Simulation-studies

    Project started: November 2000First irradiations: p (July + Sept. 01), n (Oct. 01), (Sept. 01)

    Preliminary Results of the CiS-HH SRD ProjectG. Lindstrm*, E. Fretwurst*, I. Pintilie, R. Rder, J. Stahl*

    * Uni-Hamburg, guest from NIMP, Bucharest, CiS Institute for Microsensors, Erfurt

  • Gunnar Lindstrm, CiS report, CERN 29-Nov-01

    Wacker

    Standard process

    = 3.71 kcm 4%

    Topsil

    Standard process

    = 1.12 kcm 16%

    ! ! ! !

    Resistivity profiles on 4" CiS wafersWacker and Topsil

    measured from depletion voltage on diodes

    Wacker exhibits less radial dispersion thanTopsil

  • Gunnar Lindstrm, CiS report, CERN 29-Nov-01

    Wacker

    DOFZ 72h/1150C

    = 3.02 kcm 3%

    Topsil

    DOFZ 72h/1150C

    = 3.85 kcm 9%

    ! ! ! !

    Resistivity profiles on 4" SINTEF wafersWacker and Topsil

    measured from depletion voltage on diodes

    Also for SINTEF process and after DOFZ:Wacker exhibits less radial dispersion thanTopsil

  • Gunnar Lindstrm, CiS report, CERN 29-Nov-01

    1. A first survey:

    2. The final choice:

    ! SIMS profiles reliable, symmetric wrt 140 m !! Theory predictions excellent! [O] in Cz extremely homogeneous as expected

    Depth profiles of Oxygen concentration DOFZ: 8 72 h at 1150C

    measured with improved SIMS on bevelled samples

    0 5.101 102 1.5.102 2.102 2.5.102

    depth [m]

    5

    1015

    5

    1016

    5

    1017

    5

    O-c

    once

    ntra

    tion

    [cm

    -3]

    8 h diffusion in N28 h diffusion in N212 h diffusion in N212 h diffusion in N216h diffusion in N216h diffusion in N224h diffusion in N224h diffusion in N248h diffusion in N248h diffusion in N272h diffusion in N272h diffusion in N2

    all experimental profiles normalised all experimental profiles normalised to theoretical curves wrt integrals between 50-100 mto theoretical curves wrt integrals between 50-100 mFtheor/exp = 1.03 +/- 10%Ftheor/exp = 1.03 +/- 10%

    theoretical and SIMS profiles of O-concentration for diffusion at 1150 0C(theor.): CS = 2.0e17 cm-3; diffusion constant: D = 2.0e-10 cm2/sec

    SIMS-COMPARISON-CIS REPORT 31-JAN-01 | 31.1.2001

    0 5.101 102 1.5.102 2.102 2.5.102

    depth [m]

    1015

    5

    1016

    5

    1017

    5

    1018

    O-c

    once

    ntra

    tion

    [cm

    -3]

    Cz as grown, = 8.14e17 O/cm3, = 1.7e15 C/cm3Cz as grown, = 8.14e17 O/cm3, = 1.7e15 C/cm3FZ 72h/11500C, = 1.14e17 O/cm3, = 2.9e15 C/cm3FZ 72h/11500C, = 1.14e17 O/cm3, = 2.9e15 C/cm3FZ 48h/11500C, = 9.86e16 O/cm3, = 5.8e15 C/cm3FZ 48h/11500C, = 9.86e16 O/cm3, = 5.8e15 C/cm3FZ 24h/11500C, = 5.68e16 O/cm3, = 3.3e15 C/cm3FZ 24h/11500C, = 5.68e16 O/cm3, = 3.3e15 C/cm3

    SIMS profiles of O-concentration for DOFZ at 1150 0Cand for as grown Cz-wafers - all wafers: thickness = 280 m

    SIMS-PROFILES FZ AND CZ FOR RAINER | 2.4.2001

  • Gunnar Lindstrm, CiS report, CERN 29-Nov-01

    Examples of IR absorption spectra

    IR and SIMS results in comparison:

    SIMS results: integrated average between d= 0 and 140 mIR results: averages of 4 measured samples in each case

    = 1.10 10%

    ! Agreement between SIMS and IR excellent

    Depth profiles of Oxygen concentration DOFZ: 8 72 h at 1150C

    Integrated SIMS compared to IR absorption results

    Sample# t diffusion [h] [O] SIMS [1/cm] [O] IR [1/cm] IR/SIMS 1 None, (Cz) 8.13e17 8.55e17 1.052 2 8 3.68e16 3.65e16 0.992 3 12 5.00e16 4.51e16 0.902 4 16 4.74e16 5.72e16 1.207 5 24 5.50e16 6.97e16 1.267 6 24 5.86e16 6.59e16 1.125 7 48 9.86e16 1.04e17 1.055 8 72 1.14e17 1.30e17 1.140 9 72 1.13e17 1.34e17 1.186

  • Gunnar Lindstrm, CiS report, CERN 29-Nov-01

    Wacker = 2 5 kcm, before, after oxidation

    Wacker = 1 6 kcm, before, after oxidation

    ! Little change in resistivity after oxidation! slight improvement of radial dispersion

    Resistivity profiles on 4" wafersChange due to oxidation?

    measured with 4-point probe

    FZ wafer #12

    0

    1000

    2000

    3000

    4000

    5000

    6000

    -50 -40 -30 -20 -10 0 10 20 30 40 50

    location across diameter [mm]

    resi

    stiv

    ity [O

    hmcm

    ]

    FZ wafer #14

    0

    1000

    2000

    3000

    4000

    5000

    6000

    -50 -40 -30 -20 -10 0 10 20 30 40 50

    location across diameter [mm]

    resi

    stiv

    ity [O

    hmcm

    ]

    FZ #3

    0

    1000

    2000

    3000

    4000

    5000

    6000

    -50 -40 -30 -20 -10 0 10 20 30 40 50

    location across diameter [mm]

    resi

    stiv

    ity [O

    hmcm

    ]

    FZ #1

    0

    1000

    2000

    3000

    4000

    5000

    -50 -40 -30 -20 -10 0 10 20 30 40 50

    location across diameter [mm]

    resi

    stiv

    ity [O

    hmcm

    ]

  • Gunnar Lindstrm, CiS report, CERN 29-Nov-01

    Cz Sumitomo , 600 cm

    Before oxidation: = 590 cm

    11%

    After oxidation: = 355 cm

    kcm kcm 11%

    Comparison:

    After oxidationand TD kill: = 820 cm 12%

    ! Thermal donor kill essential for final process! 1h/800C + 1min ramp to RT sufficient (?)! final larger than on as grown wafer

    Resistivity profiles on 4" Cz-wafersInfluence of thermal donors

    measured with 4-point probe

    CZ wafer #23before and after oxidation

    0

    200

    400

    600

    800

    1000

    -50 -40 -30 -20 -10 0 10 20 30 40 50

    location across diameter [mm]

    resi

    stiv

    ity [O

    hmcm

    ] after ox. before ox.

    CZ wafer #23after thermal donor anneal

    0

    200

    400

    600

    800

    1000

    1200

    -50 -40 -30 -20 -10 0 10 20 30 40 50location across diameter [mm]

    resi

    stiv

    ity [O

    hmcm

    ]

    || to flat_| to flat

  • Gunnar Lindstrm, CiS report, CERN 29-Nov-01

    Cz Sumitomo , 600 cm

    ! TD-concentration measured by DLTS can fully explain the change of resistivity

    ! proper TD killing needed in process

    DLTS and Neff by Vdep on test diodes:Diode #12:Neff = 6.88e12 cm- 625 cmNthD= 1.32e12 cm- (double charged!), measd. by DLTSeffective concentration: 2.64e12 cm-Net doping conc.: (6.88-2.64)e12 cm- =Neff,corr.=4.24e12 cm- 1014 cm

    Diode #35:Neff = 9.10e12 cm- 472 cmNthD= 2.16e12 cm- (double charged!), measd. by DLTSeffective concentration: 4.32e12 cm-Net doping conc.: (9.10-4.32)e12 cm- =Neff,corr.=4.78e12 cm- 900 cm

    After thermal donor correction: 960 cm 6%

    4-point probe measurements:(on different wafer!) after oxidation: 360 cm 11% after oxidation and TD kill: 820 cm 11%

    Resistivity of Cz-wafersInfluence of thermal donors

    Results from DLTS

  • Gunnar Lindstrm, CiS report, CERN 29-Nov-01

    Cz Sumitomo , 600 cm

    After processing including TD kill:

    = 1.34 kcm 6%

    Comparison:

    Before processingBut after oxidation+ TD kill(4-point probe)

    = 0.