Transcript Vaclav Vrba

Silicon sensors status
Václav Vrba
Institute of Physics, AS CR, Prague
IFR Praha 2004, 16th April 2004
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Václav Vrba, Institute of Physics, AS CR
Pad array design consideration
Along with the diodes, the technique used for
fabrication of bias resistors and coupling capacitors
represents an important issue:
a) polysilicon resistors – production of the tile needs about
7-8 masks; can be the source of additional yield
reduction.
b) punch through resistors – production of the tile needs
about 5 masks; easy to produce – needs to check whether
required parameters can be achieved.
c) ion implantation resistors – not considered here.
IFR Praha 2004, 16th April 2004
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Václav Vrba, Institute of Physics, AS CR
Design consideration: Polysilicon resistors
Bias lines
Top view
Bias
resistor
Coupling
capacitor
Direct
contact on
diode – e.g.
for testing
Vertical
cross section
IFR Praha 2004, 16th April 2004
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Václav Vrba, Institute of Physics, AS CR
Design consideration: Polysilicon resistors
IFR Praha 2004, 16th April 2004
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Václav Vrba, Institute of Physics, AS CR
Design consideration: Punch through resistors
Bias lines
Top view
Bias
resistor
Coupling
capacitor
Direct
contact on
diode – e.g.
for testing
Vertical
cross section
IFR Praha 2004, 16th April 2004
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Václav Vrba, Institute of Physics, AS CR
Design consideration: a partial summary
a) polysilicon resistors:
should not be a problem to have resistors  10 M;
capacitors  1-10 nF.
b) punch through resistors:
resistors to be tested; if acceptable then it is a simple
solution;
capacitors as a).
Compatibility of process for variants a) and b) on one
wafer? Option a) as a baseline for main sensor tile?
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Václav Vrba, Institute of Physics, AS CR
Pre-prototyping
IFR Praha 2004, 16th April 2004
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Václav Vrba, Institute of Physics, AS CR
Tests outlines
A) Diode tests
a) I-V curves:
- Vbreak-down  Vop
- Ileak @ Vop < cca 30 nA/cm2
b) C-V curves:
 determination of Vfull-depletion; Vop = Vfull-depletion + 50 V.
c) Long term stability tests:
- Ileak @ Vop .
Tile should be rejected if:
- Vbreak-down < Vop
- Ileak > I crit (to be defined).
IFR Praha 2004, 16th April 2004
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Václav Vrba, Institute of Physics, AS CR
Electric characterization
IFR Praha 2004, 16th April 2004
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Václav Vrba, Institute of Physics, AS CR
Tests outlines
B) Bias resistors
a) shorts
b) breaks
c) outside specifications
C) Capacitance couplings
a) shorts
b) breaks
c) outside specifications
IFR Praha 2004, 16th April 2004
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Václav Vrba, Institute of Physics, AS CR
Tests outlines
Basic equipment:
-
micromanipulators with contact needles;
I-V: Keithley 487 A;
C-V: LCR meter HP
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Václav Vrba, Institute of Physics, AS CR
Probestation
IFR Praha 2004, 16th April 2004
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Václav Vrba, Institute of Physics, AS CR