Status on CMOS sensors

1
Status onCMOS sensors

• Auguste Besson
• on behalf of
• IRES/LEPSI M. Deveaux, A. Gay, G. Gaycken, Y.
  Gornushkin, D. Grandjean,
• S. Heini, A. Himmi, Ch. Hu, H. Souffi-Kebbati,
  I. Valin, M. Winter,
• G. Claus, C. Colledani, G. Deptuch, W. Dulinski
• (M6/M8 DAPNIA Y. Degerli, N. Fourches, P. Lutz)

• Develop. of large CMOS sensors (3-T/pixel)
• Caracterization of the technology without
  epitaxy
• RD on fast sensors.
• 2004 schedule and summary

2
History

• MIMOSA 1,2,4,5 tested at CERN-SPS with 120 GeV/c
  ?-
• M6 tests in progress
• M7 available soon
• SUCESSOR 2 (SUCIMA PROJECT) beam test in 2003
• 40 ?m pitch, no epitaxial layer.
• 2003 M4, M5, M6 tests, M7 fabricated

3
3-T/pixel large CMOS sensors (M5)

• AMS 0.6 ?m (M1 like)
• reticle size 19.4 x 17.4 mm2
• 512 x 512 pixels
• (/ each of 4 matrices)
• 17x17 ?m pitch
• 4 sub-matrices per sensors, read-out in parallel
• 6 wafers (6) built in 2001
• 3 wafers thinned down to 120 ?m (2 in 2003)
• 2002 results
• Yield 20-30
• ?det ? 99 ?sp 1.7 ?m ?ltgaingt 0.2

4
3-T large sensors 2003 (2)

• Beam test at SPS (2003)
• 3 sensors
• 120 GeV/c ?-
• Performance uniformity tests
• between sub-matrices, sensors
• diode size comparisons

Small diode (3x3 ?m2)
Big diode (5x5 ?m2)
5
3-T large sensors results (3)

• submatrices have similar properties
• 1 dead column / 512 (i.e. 0.2 det
  inefficiency)
• single point resolution ? 2.5 ?m (still
  improvable)
• Effect of particle incidence
• chip turned w.r.t. beam direction
• charge as expected

6
3-T large sensors M5-B (4)

• Mimosa 5-B
• 23 wafers produced in oct. 2003
• Slightly improved fabrication process
  (metalisation)
• should reduce dead columns rate.
• should improve rate of good chips (yield)
• setting up thinning to 15 ?m (Nov 03)
• (with a Si wafer on the electronics side for
  handling)
• Application to bio-medical imaging (20-30 keV e-)
  

7
3-T large sensors application (5)

• STAR extension of the Vertex Detector (2006)
• charm physics ? small radius, granular and thin
  detector
• 2 pixel layers ? ? 1000 cm2 R(layer 1) ? 2 cm
  R(layer 2) ? 4 cm
• M5 performances are close to the STAR
  requirements
• started a collaboration with LBL (and BNL)
• first MIMO?1 prototype in summer 2004 (new TSMC
  0.25 ?m tech.)

• Requirements
• ?pt 3 ?m
• 2.6 kRad/year
• 2.1010 neq/cm2/year
• read out time 10-20 ms
• Power ? 100 mW/cm2
• sensor thickness ? 50 ?m
• Room temperature

• What to improve ?
• read out time ( 24 ms)
• sensor thickness ( 120 ?m)
• electronic noise (room T)
• yield (not crucial)

8
No epitaxial layer prototypes (M4)

• Properties
• AMS 0.35 ?m witout epitaxial layer.
• Low doped substrate
• ? increases ?e
• 120 GeV/c ?- SPS beam tests
• Eff ? 99.5
• resolution ?sp 2,5 ?m (new)
• Fabrication processes with
• epitaxial layer is not mandatory !

9
No epitaxial layer (M4) (2)

• Rad. tol. studies
• 200 kRad (x-rays),
• 1.4 1011 neq/cm2
• S/N ? when T ?
• If T ? 20C ? no obvious effects on efficiency
  and spatial resolution
• Radiation effects are negligible at this level
  (200 kRad 1.4x1011 n/cm2)

10
No epi. SUCCESSOR 2
SB1 Charge (1,9,25 pixels)

• SUCCESSOR 2 (M4 like)
• bio-medical imaging, SUCIMA project.
• (no epi. layer , AMS 0.35 ?m)
• 40x40 ?m2 pixels
• beam tests (oct. 2003)
• different sub-structures tested
• (3T pixel, Self-Bias pixels with 2 different
  diode sizes)
• eff ? 99.9
• ?sp 5-6 ?m (2 x M4 with 20 ?m pitch)
• best performances for large diodes SB

Noise vs T
X resolution vs T
S/N vs T
?
11
RD on fast sensors

• M1-M5 ? 1M pixels read-out in 1-10 ms
• FLC ? 1st VD layer must be read-out in 25-50 ?s
  (beamstrahlung)
• potentially tremendous data flow
• e.g. 15 bits/pixels, t25 ?s ? 500 Gbits/s/106
  pixels !
• main goal fast signal treatment AND data
  compression integrated in the sensor
• Fast // read out of short columns
• Different prototypes with different signal
  treatment
• M6 (with DAPNIA) tests in 2003,
• individual pixels and discri work fine, but large
  spread of pixel caracteristics (pedestal, noise,
  gain ?)
• M7 available soon, tests in 2003-04
• M8 (with DAPNIA) submitted in Nov., tests in
  2004

12
Summary

• Large sensors (M5) (1M pixels, AMS 0.6 ?m )
• ready to be used for a real detector
• 2nd fabrication (23 wafers) with a better yield
  expected
• thinning down to 15 ?m in progress
• application to extension of STAR Vertex detector
  in 2006
• No epitaxial layer sensors (M4, SUC 2)
• validated for m.i.p. detection (eff ? 99.5, ?sp
  2,5 ?m)
• fits industrial CMOS fabrication tendancy
• Fast response sensors (M6, M7, M8)
• studies fab. techno., charge collection system,
  signal treatment architecture ? read out speed,
  efficiency, zero sup., power diss. etc.
• 2003/2004 schedule
• M5-B tests ? yield, thinning
• M?1 ? available in summer 2004, tests in autumn
• fast sensors 2 prototypes
• M7 and M8 tests
• charge collection studies ? ionising radiation
  tol.