Rutherford Appleton LaboratoryParticle Physics Department

G. Villani IEEE NSS Rome, October 2004

Design and Characterization of a Novel, Design and Characterization of a Novel, Radiation-Resistant Active Pixel Sensor in Radiation-Resistant Active Pixel Sensor in

a Standard 0.25 a Standard 0.25 m CMOS Technologym CMOS Technology

P.P. Allport, G. Casse, A. Evans, M. Tyndel, R. Turchetta, J.J. Velthuis, G. Villani

Rutherford Appleton LaboratoryParticle Physics Department

G. Villani IEEE NSS Rome, October 2004

OutlineOutline

• CMOS APS detectors: principle & characteristics• Novel CMOS detector structure• HEPAPS3• Conclusions

Rutherford Appleton LaboratoryParticle Physics Department

G. Villani IEEE NSS Rome, October 2004

MAPS CMOS detectorsMAPS CMOS detectors

readout

Column parallel ADC

Data processing -out stage

control

3 MOS APS structure

Detector and readout integrated onto the same substrate

≈10

Rutherford Appleton LaboratoryParticle Physics Department

G. Villani IEEE NSS Rome, October 2004

CMOS detectors for HEPCMOS detectors for HEP

Generated charge diffuses through epitaxial layer and substrate untilrecombines or gets collected by cathode

-

-

+

+

+

+

+

-- -

--

-

P++

Pepi

PwellNwell

Internal electric field 3D viewVbias = 2V applied to N+

Well 30 ns Transient Electron Current

Rutherford Appleton LaboratoryParticle Physics Department

G. Villani IEEE NSS Rome, October 2004

Reference : HEPAPS2 0.25 μm CIS TSMC

N

P

epi

subs

Simulated ∆v in-cell

Tests results ∆v in-cell

CMOS detectors for HEP-Charge collection and response timeCMOS detectors for HEP-Charge collection and response time

Rutherford Appleton LaboratoryParticle Physics Department

G. Villani IEEE NSS Rome, October 2004

CMOS detectors for HEP-Radiation HardnessCMOS detectors for HEP-Radiation Hardness

T = 300 K

T = 253 K

No RAD

RAD 1014

Test results S/N ratio vs number of pixels

Charge collected mainly by diffusion: Radiation Bulk damage seriously impacts onto charge collection efficiency

5.0

2

int

-2-int

ee

,,,

egrrmsRSTrms

coll yxntyx

N

S

Example of S/N calculation under Hard Reset assumption Vbias = 2VHEPAPS2 0.25 μm CIS TSMC

Example of simulation radiation degradation@ to bulk damage Ф = 1014 24GeV p

J. VelthuisJ. Velthuis University of Liverpool University of Liverpool

Rutherford Appleton LaboratoryParticle Physics Department

G. Villani IEEE NSS Rome, October 2004

Novel CMOS structure for HEPNovel CMOS structure for HEPDeep N Well process allows electric field to be introduced into active region

N

P

epi

subs

Internal electric field plot

Deep N Well

Cell structure comparison

Rutherford Appleton LaboratoryParticle Physics Department

G. Villani IEEE NSS Rome, October 2004

Deep N Well Epi collected chargeDeep N Well Epi collected charge

HEPAPS DNW-Epi Heavy Ion MIP Simulation Results:

Collection time max: 8 nS

<Collected charge> (Ф = 0) = 261 e-

<Voltage Drop> (Ф = 0) = 1.8 mV

Leakage Current (Ф = 0 ) 65 fA

Capacitance ( Ф = 0 ) 22 fF

HEPAPS DNW-Epi simulation

conditions:

Vbias = 2V

Cstray = 2 fF

Tint = 20 ns

3x3 Cells ( size 15x15 m)

Ilk vs. bias voltage Capacitance vs. bias voltage

Rutherford Appleton LaboratoryParticle Physics Department

G. Villani IEEE NSS Rome, October 2004

Radiation Hardness and Signal to noise ratio comparisonRadiation Hardness and Signal to noise ratio comparison

No RAD RAD 1014

Deep N Well Epi Example of S/N calculation HR Vbias = 2 APS2 0.25 μm DNW 8 m Epitaxial layer TSMC MS

HEPAPS2 Example of S/N calculation HR Vbias = 2 APS2 0.25 μm 8 m Epitaxial layer TSMC CIS

Rutherford Appleton LaboratoryParticle Physics Department

G. Villani IEEE NSS Rome, October 2004

HEPAPS3 Deep N WellHEPAPS3 Deep N WellN

P

subs

TSMC MS 0.25 mNo epitaxial layerDifferent flavors on chip

HEPAPS3HEPAPS3: No Epitaxial layer, Lowly Doped Substrate TSMC MSSlower collectionHigher spreadCharge collected much dependent on diffusion in undepleted substrateHEPAPS3 Simulation Results:HEPAPS3 Simulation Results:

Collection time max: 14 nS

<Collected charge> (Ф = 0) = 338 e-

<Voltage Drop> (Ф = 0) = 1.9 mV

Leakage Current (Ф = 0 ) 65 fA

Capacitance ( Ф = 0 ) 26 fF

Rutherford Appleton LaboratoryParticle Physics Department

G. Villani IEEE NSS Rome, October 2004

HEPAPS3 test resultsHEPAPS3 test results

HEPAPS3: No Epitaxial layer Lowly Doped Substrate TSMC MSLarge signalHuge cluster size( charge diffusion trough undepleted substrate)

HEPAPS3: example of cluster in S/N106Ru source

J. VelthuisJ. Velthuis University of Liverpool University of Liverpool

HEPAPS3: example of cluster signal distribution DNW106Ru source

HEPAPS3: example of noise signal distribution DNW

Rutherford Appleton LaboratoryParticle Physics Department

G. Villani IEEE NSS Rome, October 2004

Topology optimization of MAPS still ongoing, but future HEP experiments call for uncompromisingly high radiation resistant structures

ConclusionsConclusions

HEPAPS3 preliminary tests results and simulations suggest Deep N Well process with epitaxial layer might show good performances at high level of radiation

Synergy between new design topologies and Deep N Well process required to fully exploit the potential benefits

Deep N Well with Epitaxial layer introduces drift component in collection charge process

Rutherford Appleton LaboratoryParticle Physics Department

G. Villani IEEE NSS Rome, October 2004

HEPAPS2 simulation 4 Diodes versionHEPAPS2 simulation 4 Diodes version

Simulation shows better charge collection at 1014

IrradiationTests ongoing

Cell structure