PXL Electronics Status update for HFT TC meeting on October 14, 2010 at BNL 1HFT TC 05/11/2010 - LG.
Outline STAR HFT Upgrade: PXL detector CMOS Pixel Sensor requirements Sensors optimization
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Transcript of Outline STAR HFT Upgrade: PXL detector CMOS Pixel Sensor requirements Sensors optimization
A Reticule Size CMOS Pixel Sensor (ULTIMATE) Dedicated to the STAR HFT Upgrade
Thanh Hung PHAM
on behalf of the IPHC (Strasbourg) PICSEL group
Outline STAR HFT Upgrade: PXL detector
CMOS Pixel Sensor requirements
Sensors optimization
Recent ULTIMATE test results
Lab test and Beam test
Summary + Perspectives
IPHC [email protected] 226-30/09/2011 TWEPP 2011STARSTAR
Heavy Flavor Tracker (HFT) at STAR
HFT is an upgrade of the inner tracking system of STAR detector comprising :
SSD – Silicon Strip Detector IST – Inner Silicon Tracker PXL – Pixel Detector (2 layers at 2.5 & 8 cm)
Physical Goals : Identification of mid rapidity Charm and Beauty mesons and baryons through direct reconstruction and measurement of the displaced vertex with excellent pointing resolution
~ 150 µm
TPC SSD IST PXL~1 mm ~300 µm ~250 µm
vertex<30 µm
IPHC [email protected] 326-30/09/2011 TWEPP 2011STARSTAR
PIXEL SENSORS FOR HFT
Sensors Requirements Multiple scattering minimisation:
Sensors thinned to 50 µm, mounted on a flex kapton/aluminum cable
X/X0 = 0.37% per layer
Sufficient resolution to resolve the secondary decay vertices from the primary vertex
< 10 µm
Luminosity = 8 x 1027 / cm² / s at RHIC_II ~200-300 (600) hits / sensor (~4 cm2) in the
integration time window Short integration time ~< 200 µs
Low mass in the sensitive area of the detector airflow based system cooling
Work at ambient (~ 35 °C ) temperature Power consumption <~ 150 mW / cm²
Sensors positioned close (2.5 - 8 cm radii) to the interaction region
~ 150 kRad / year few 1012 Neq / cm² / year
MAPSRDObuffers/drivers
4-layer kapton cable with aluminium tracesAluminum conductor Ladder Flex Cable
Ladder with 10 MAPS sensors (~ 2×2 cm² each)
carbon fiber sector tubes
(~ 200µm thick)
Insertion from one side2 layers10 sectors 4 ladders/sector
Leo Greiner @ St Odile CMOS Workshop, Sep 2011
IPHC [email protected] 426-30/09/2011 TWEPP 2011STARSTAR
Main characteristics of ULTIMATE (Mimosa-28) sensor
0.35 μm process with high-resistivity epitaxial layer column // architecture with in-pixel CDS & amplification end-of-column discrimination and binary charge encoding,
followed by zero suppression logic active area: 960 columns of 928 pixels (19.9×19.2 mm²) pitch: 20.7 μm ~0.9 million pixels
charge sharing >~ σsp 3.5 μm expected tr.o. ≤ 200 μs ( ~ 5×103 frames/s)
suited to >106 part./cm²/s 2 outputs at 160 MHz ≤ 150 mW/cm² power consumption Radiation tolerant (~150 kRad/year & 3x1012 neq/cm²)
Submitted by end-January 2011
Received early April 2011
IPHC [email protected] 526-30/09/2011 TWEPP 2011STARSTAR
Main characteristics of ULTIMATE (Mimosa-28) sensor (suite)Based on expertise's acquired from
M26 chip for EUDET, the design of ULTIMATE has been optimized for STAR environment
Row sequencer
Minimize the delays of signals over ~2cm
8 analog outputs
(Test purpose only)
Pixel Optimization:
Radtol ~ 150 kRad/year & 3x1012Neq/cm²/year
Consumption < 150mW/cm2
Large reticule size (~2cmx2cm)
End-column 960 discriminators:
Offset compensation
Encoding & Zero suppression logic:
STAR conditionsBias current & Ref DACs
Pixels Ref Regulator &Analog Power Supply regulator (Optional)
Reduce I/O pads Programmable (Ref
Regulator)
JTAG Configuration
High data size & Rate:
2 Memories 2048x32-bits
2 Outputs at 160 MHz
I/O Pads: Powers, LVDS & Controls
PLL (Optional)
IPHC [email protected] 626-30/09/2011 TWEPP 2011STARSTAR
Pixel optimization
Slct_Row
16 p
ix
Slct_Gr
Slct_Row
16 p
ix
Slct_Gr
Slct_Row
Slct_Row
Slct_Row
Column-levelDiscriminator
RD
CALIB
LATCH
Slct_Row
~ 2 cm long!!!
Radiation Tolerant and Power Consumption
Enclosed layout transistor M4
Tradeoff between Power Consumption and Radiation Tolerant -> Optimization of pixels size (20.7x20.7µm²)
~2x2cm2 reticule size
Multiplex pixels output to reduce the capacitance of output nodes
Optimization of output buffer stage (transistors M7, M8 & M9) in order to drive 2cm of metal line
R ~ 1.9 KΩC ~ 4 pF
Select_GrM9
Out group
~3µA
~50µA
IPHC [email protected] 726-30/09/2011 TWEPP 2011STARSTAR
Digital conception challenges
2cm of row controls signal Row sequencer logic : Uniformly distributed with dispersion < 500ps
Optimization of zero suppression to cope with STAR environment Up to 9 states /row Segmented by 15 groups of 64 columns -> Symmetrical distributions of digital controls over ~2cm (at
50MHz) High density & High speed readout :~0.9 Mpix & < 200µs frame readout
2 memories of 2048x32 bits 2 outputs of 160MHz Increase frequency up to 160MHz
Layout constraint : 2261µmx19872µm The output of SRAM is serialized at 160MHz250µm
19295µm
200 ns
22
61
µm
19872 µm
Memory managementMUX
SDS
SRAM 2048 x 32 1 SRAM 2048 x 32 2Seq
Serializer
Row sequencer
IPHC [email protected] 826-30/09/2011 TWEPP 2011STARSTAR
On-chip Regulators
Internal Pixel References Voltages
cz
RA
RB
c1
Vbg
Vbias
Vdda
Vclamp
Mz
Msf1
Msf2
Error amplifier Serial RC network
Buffer Output stage
MpwVfb
c2
74.8 nV/√Hz @ 1 kHzNoise
1.9-2.3VOutput range
< 1mWConsumption
> 5nFCapacitive Load
0.0389 mm²Size
PSRR
Vcl
Ultimate
~2x2cm²
Ladder of 10 Ultimate sensors using external Vcl
Crosstalk between sensors through Vclp
Integrated VCL Regulator
Reduce crosstalk between sensors
Reduce material budget: no extra decoupling capacitors
52 dB @ 10 kHz
38 dB @ 1 MHz
MAPSRDObuffers/drivers
4-layer kapton cable with aluminium traces
IPHC [email protected] 926-30/09/2011 TWEPP 2011STARSTAR
LAB TEST RESULTS
Analogue output noise (Mode Test):
Ultimate Sensor
Temperature
Calib peak
(UADC)
ENC (e-)
CCE
Seed pixel
2x2 pixels
3x3 pixels
5x5 pixels
~20 °C 395 13.8 24% 62% 82% 94%
~35 °C 385 16.4 24% 62% 83% 96%
~45 °C 369 20.7 23% 63% 85% 99%
ENC ~ < 15 e- (On-chip reference regulator)
Gain ~ 65µV/e-
Good Noise uniformity
The CCE is very little sensitive to Temperature and Analog Power Supply variations
Conditions:
Pixel array scan at 40MHz
T = 20°C
Nominal JTAG load
Analog Power Supply (VddA) = 3.3V
Charge Collection Efficiency (Mode Test):
Analog Power Supply
Calib peak
(UADC)ENC (e-)
CCE
Seed pixel
2x2 pixels
3x3 pixels
5x5 pixels
Vdd_a = 3.3V 395 13.8 24% 63% 82% 95%
Vdd_a = 3V 390 13.9 24% 62% 83% 95%
IPHC [email protected] 1026-30/09/2011 TWEPP 2011STARSTAR
Scan of matrices pixel and discriminator
Sub-matrix A
(Column 1-240)
Sub-matrix B
(Column 241- 480)
Sub-matrix C
Column 481 – 720)
Sub-matrix D
Column 721 -960
Temporal Noise (mV) 1 0.95 0.92 0.9
Fixed Pattern Noise (mV) 0.57 0.49 0.48 0.47
Sub-matrix ASub-matrix A
IPHC [email protected] 1126-30/09/2011 TWEPP 2011STARSTAR
Beam Test Results (July 2011)
Conditions:
CERN-SPS 120 GeV π− beam
BT made of 6 Ultimate sensors(20µm thick epi)
T = 20°C & 30°C
ionizing radiation dose: 0&150 kRad
Analog power supply : 3V & 3.3V
Results:
Efficiency > 99.5 % with a fake hit rate << 10-4
Spatial resolution < 4 µm
IPHC [email protected] 1226-30/09/2011 TWEPP 2011STARSTAR
Conclusion & perspectives
ULTIMATE sensors for the PXL detector of STAR HFT experiment has been designed and tested in 2011
The lab test and beam test showed : Robust regarding temperature variations Operational with analog power supply down to 3V High detection efficiency ( > 99%) with very low fake event of beam test High yield : > 90%
12 sensors fully functional 4 with 1% of death pixels
The Ultimate sensor fulfils all STAR HFT specifications
Engineering run of ULTIMATE sensor (12 wafers) is being submitted in September for equipping the engineering prototype detector
Start of run at RHIC in FY 2012
The ULTIMATE sensor development allows to accumulate expertises for future sensor designs (ALICE, AIDA, CBM, EIC, …)
IPHC [email protected] 1326-30/09/2011 TWEPP 2011STARSTAR
BACKUP SLIDES
IPHC [email protected] 1426-30/09/2011 TWEPP 2011STARSTAR
MIMOSA26 with high resistivity EPI layer (1)
Charge collection efficiency for the seed pixel, and for 2x2 and 3x3 pixel clusters
Signal to noise ratio for the seed pixel before irradiation and after exposure to a fluence of 6 x 1012 neq / cm²
~ 76 %~ 57 %~ 22 %20 µm
~ 91 %~ 78 %~ 31 %15 µm
~ 95 %~ 85 %~ 36 %10 µm
~ 71 %~ 54 %~21%
3x32x2seedEPI thickness
3x32x2Seed
CCE (55Fe source)
High resistivity (~400 .cm)Standard (~10 .cm) 14 µmEPI layer
(a)
EPI thick
10.7
After 6x1012 neq/cm²Before irradiation
--------
28
22
After 6x1012 neq/cm²Before irradiation
~ 3620 µm
~ 4115 µm
~ 3510 µm~ 20
(230 e-/11.6 e-)
S/N at seed pixel
(106Ru source)
High resistivity (~400 .cm)Standard (~10 .cm) 14 µmEPI layer
(b)
~ 76 %~ 57 %~ 22 %20 µm
~ 91 %~ 78 %~ 31 %15 µm
~ 95 %~ 85 %~ 36 %10 µm
~ 71 %~ 54 %~21%
3x32x2seedEPI thickness
3x32x2Seed
CCE (55Fe source)
High resistivity (~400 .cm)Standard (~10 .cm) 14 µmEPI layer
(a)
EPI thick
10.7
After 6x1012 neq/cm²Before irradiation
--------
28
22
After 6x1012 neq/cm²Before irradiation
~ 3620 µm
~ 4115 µm
~ 3510 µm~ 20
(230 e-/11.6 e-)
S/N at seed pixel
(106Ru source)
High resistivity (~400 .cm)Standard (~10 .cm) 14 µmEPI layer
(b)Christine HU@TWEPP 2010