SOIPD 2009SOIPD 2009

SOIPDSOIPD

KEK-LBNL-Padova

collaboration

SOIPD 2009SOIPD 2009

Silicon On Insulator (SOI) detectorsSilicon On Insulator (SOI) detectors

SOI-2 (2008)SOI-2 (2008)

• 0.20um OKI FD-SOI technology• 128172 digital pixels (2020 um2)• 40172 analog pixels (2020 um2)• Optimized for low leakage current• Currently under test

SOI-2-IMAGER (2009)SOI-2-IMAGER (2009)

• 0.20um OKI FD-SOI technology• 256256 analog pixels (13.7513.75 um2)• 4 analog outputs• 5mm chip, 3.2mm active • Just delivered

● CMOS electronics implanted on a thin silicon layer on top of a buried oxide (BOX): ensures full dielectric isolation, small active volume and low junction capacitance

● Radiation sensors can be built by using a high resistivity substrate and providing a technology to interconnect the substrate through the BOX

SOI-1 (2007)SOI-1 (2007)

• 0.15um OKI FD-SOI technology• 16050 digital pixels (1010 um2)• 160100 analog pixels (1010 um2)• MIPs detection• First radiation damage tests

SOIPD 2009SOIPD 2009

SOI-1 Tests on Analog and Digital PixelsSOI-1 Tests on Analog and Digital Pixels Tests with a 1060nm IR laser (analog section)Tests with a 1060nm IR laser (analog section)

• IR laser spot: 20um;

• analog section tested for different Vd values;

• signal pulse height measured in a 5×5 matrix, centered around the laser spot centre;

• signal increases as √Vsignal increases as √Vdd as expected (increasing depletion region) until Vd 9 ≃V, where it saturates; it decreases for Vd ≥ 15 (transistor back- gating).

• IR laser spot: 5um;

• pixel matrix scanned in 1um steps;

• position reconstructed by the center of gravity of the reconstructed cluster charge;

• resolution calculated by the spread of the reconstructed cluster position for events taken at each point in the scan and for different S/N values;

• resolution scaled as the inverse of S/Nresolution scaled as the inverse of S/N, as expected (continuous line).

Cluster pulse heightCluster pulse height

Single Point ResolutionSingle Point Resolution

Tests with High Energy Tests with High Energy Particle BeamParticle Beam

(digital section)(digital section)

• chip tested on the 1.35 GeV electron beam-line at the Advanced Light Source (ALS);

• hit multiplicity observed in the digital pixels for events taken with and without beam

• a clear excess of hits can be seen in the presence of beam

SOIPD 2009SOIPD 2009

SOI-1 Radiation Hardness TestsSOI-1 Radiation Hardness Tests

• Irradiation performed at the BASE Facility of the LBNL 88-inch Cyclotron with 30 MeV protons30 MeV protons on single transistors;

• study of the variation in the threshold voltage for the nMOS test transistor as a function of the proton fluence;

• irradiation performed up to a total dose of 600 kRad. ≃

• the total threshold variation is indeed significant ( 100 mV) also for a low substrate bias (i.e. Vd = 1 V). The effect is much larger than what would be expected at such doses from radiation damage in the transistor thin gate oxide and is clearly due to charge build-up in the thick buried oxide

•similar results are obtained for the pMOSFET characteristics.

An initial substrate voltage Vd = 5 V was used, but after a fluence of about 1×1012 p/cm2 the transistor characteristics could not be properly measured, and a reduced substrate bias of Vd = 1 V needed to be apply in order to recover the transistor characteristics.

• Irradiation performed at the LBNL 88-inch Cyclotron with 1-14 MeV neutrons1-14 MeV neutrons on the analog pixel matrix;

• study of the sensor noise before and after irradiation as a function of the depletion voltage at room temperature;

• irradiation performed up to a total fluence of 1.2×1013 n/cm2;

• a noise increase was observed after irradiation, varying from +25% for Vd = 5 V, to +52% for Vd = 20 V. This is interpreted as due to radiation-induced increase of leakage current in the sensor substrate

Ionizing radiationIonizing radiation Non Ionizing radiationNon Ionizing radiation

Vd = 10V

SOIPD 2009SOIPD 2009

SOI-1 Tests & SimulationsSOI-1 Tests & Simulations

• Ids vs Vgs curve is drawn for different values of substrate bias

• Threshold voltage is extracted from maximum gm in simulations (left plot)

• Same procedure is used on experimental data (right plot)

TCAD simulationTCAD simulation IIdsds vs V vs Vgsgs curve curveExperimental dataExperimental data

• Backgating is much less effective in simulations

• Hypothesis: BOX = large and extended gate ! are there some 3D effects (e.g. currents flowing on the side)?

VVthresholdthreshold extraction extraction

SOIPD 2009SOIPD 2009

Backgating reductionBackgating reduction

1.E-12

1.E-11

1.E-10

1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

0 0.3 0.6 0.9 1.2 1.5 1.8

Vgs (V)

Ids

(A

)

Vback = 0V

Vback = 2V

Vback = 4V

Vback = 6V

Vback = 8V

Vback = 10V

Vback = 12V

Vback = 15V

1.E-12

1.E-11

1.E-10

1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

-0.2 0.3 0.8 1.3 1.8

Vgs (V)

Ids

(A)

Vback = 0V

Vback = 2V

Vback = 4V

Vback = 6V

Vback = 8V

Vback = 10V

Vback = 12V

Vback = 15V

PSUB ringPSUB ring surrounding the transistorsurrounding the transistor floatingfloating

PSUB ringPSUB ring surrounding the transistorsurrounding the transistor groundedgrounded

Experimental DataExperimental Data● The substrate voltage acts as a back-gate, changing the transistor threshold until making it unable to work for voltages > 16V.

● The effectiveness of placing p+ implants close to the transistor to mitigate the problem has been investigated, both with simulation and with experimental measurements.

TCAD SimulationTCAD Simulation

PSUB grounded actually limits the PSUB grounded actually limits the backgating effect!backgating effect!

SOIPD 2009SOIPD 2009

SOI-2 TestsSOI-2 Tests

M13 NMOS (L = 0.50um, W = 250um, Core, Norm Vt, Body Tie)

1.E-12

1.E-11

1.E-10

1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

-0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8

Vgs (V)

Ids

(A)

(0) pre irr

(1) 3 krad

(2) 10 krad

(3) 16krad

(4) 23 krad

(5) 30 krad

(6) 36 krad

(7) 43 krad

(8) 50 krad

(9) 56 krad

M5 PMOS (L = 0.50um, W = 250um, Core, Low Vt, body float)

1.E-11

1.E-10

1.E-09

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8

Vgs (V)

Ids

(A)

(0) pre irr

(1) 3 krad

(2) 10 krad

(3) 16krad

(4) 23 krad

(5) 30 krad

(6) 36 krad

(7) 43 krad

(8) 50 krad

(9) 56 krad

• X-ray irradiation on 0.20um technology transistors up to a total dose of 56 krad (SiO2) with Vback= 5V during irradiation; • PMOS transistors show no increment on leakage current;• leakage current for NMOS transistors is still at acceptable levels.

●● Radiation Damage TestsRadiation Damage Tests

●● Test on the detectorTest on the detectorDigital pixelsDigital pixels90Sr, V

dep = 35 V

• Analog pixels tested at LBNL ALS with 1.5 GeV e-: S/N~15-20 and ENC~20-30 e- up to 50 MHz clock frequency and V

dep=5 V

(stronger effect of back-gating w.r.t. 0.15 m process)• Digital pixels operable up to V

dep=35 V, proof of functionality

achieved with 90Sr source

Analog pixelsAnalog pixels1.5 GeV e-, V

dep = 2 V

SOIPD 2009SOIPD 2009

SOI-2 ImagerSOI-2 Imager

SOIPD 2009SOIPD 2009

3D detector3D detector

SOIPD 2009SOIPD 2009

Attività 2010Attività 2010

• Caratterizzazione SOI imager come rivelatore particelle al minimo

• Caratterizzazione SOI imager back-illuminated come rivelatore di fotoni

• Studio back-gating via IEEM

• Studio 3D detector

• Seconda produzione SOI-3D

SOIPD 2009SOIPD 2009

Attività gruppo e serviziAttività gruppo e servizi

• Progetto, disegno, test Progetto, disegno, test nuove mezzaninenuove mezzanine

• Test sensoriTest sensori• Test beamTest beam• Misura radiation Misura radiation

hardness con IEEMhardness con IEEM

• Messa a punto IEEMMessa a punto IEEM

6 m/u6 m/u• Progettazione e test nuove Progettazione e test nuove

mezzanine mezzanine 3 m/u + 1 m/u CAD3 m/u + 1 m/u CAD

• Test dispositivi Test dispositivi 5 m/u 5 m/u

• Piccoli interventi OM 2 Piccoli interventi OM 2 m/um/u

SOIPD 2009SOIPD 2009

• Bisello RN 30

• Candelori 30

• Giubilato 30

• Mattiazzo 30

• Nigro 100

• Silvestrin 100

• Wyss 30

• Gerardin 70

• Mint 2 ke

• Mest 4 missioni LBL

1 missione KEK

1 conferenza

1 m/u test beam 15

• Cons. qp produzione

mat. test lab.

mezzanine 40