First results with non-irradiated and heavily irradiated microstrip trenched detectors
Ionization versus displacement damage effects in proton irradiated
Transcript of Ionization versus displacement damage effects in proton irradiated
Ionization versus displacement damage effects in proton irradiated CMOS sensors manufactured in deep submicron processV. Goiffon1 ([email protected])P. Magnan1, O. Saint-pé2, F. Bernard3, G. Rolland31 Université de Toulouse, ISAE, 2 EADS Astrium, 3 CNES
Test chip :• 0.18 µm CMOS CIS technology• Dedicated photodiode doping profiles• Shallow trench isolations (STI)• 128 x 128 pixel array, 3T, 10µm pitch• Larges photodiodes (>104 µm²)• Other test structures (MOSFETs, Gated-diodes…)Proton irradiation :• Facilities : KVI, UCL, Isotron• Energies : 7.4 to 200 MeV• Fluences : 5 x 109 to 3 x 1011 H+/cm²
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Peripheral dark current
IC1, 8.8×109 H+/cm2, 50MeV
IC2, 1.5×1010 H+/cm2, 100MeV
IC3, 2.4×1010 H+/cm2, 184MeVIC1 no irrad.IC2 no irrad.IC3 no irrad.
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Reverse voltage (V)
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2000x5µm2 photodiode dark currents
IC1, 8.8×109 H+/cm2, 50MeV
IC2, 1.5×1010 H+/cm2, 100MeV
IC3, 2.4×1010 H+/cm2, 184MeVIC1 no irrad.IC2 no irrad.IC3 no irrad. A
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Proton irradiations only induce large dark current increases … …dominated by the perimeter contribution…
…due to ionizing dose induced STI trapped charges and
interface states.
Effects on large photodiodes
Overview
Experimental
Effects on CMOS sensors Perspectives
• No photoresponse degradation , no voltage shift, no gain reduction
No sign of electric field enhancement at the Si-STI interface
Displacement damages still play a significant role in uniformity
degradation
• Photodiode hardened against ion-izing dose effect could conse-quently reduce proton irradiation effects
• In-pixel gated photodiode (B. Hancock, Proc. SPIE 4306, 2001) seems promising
• Multi level random telegraph signals will be studied in detail
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Time (s)
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Proton induced RTS
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Dark current (fA)
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pixel valuemean value
Displacement damages effects on mean dark current are negligible…
… in front of ionizing dose : peripheral STI is responsible
Goal : Study of proton irradiation effects on CMOS sensorsmanufactured in a deep submicron technology dedicated to imaging applications
Test structures : pixel array + isolated large photodiodes
Main result : Proton irradiations mainly induce dark current increases due to ionizing interactions
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Displacement damage dose (TeV/g)
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Dark current increase vs. displacement damage dose
MeasurementComputed displacement contribution
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Ionizing dose (Gy)
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Dark current increase vs. ionizing dose
Proton irrad.Proton irrad. without hot pixels60Co irrad. (worst case)
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Dark current (fA)
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MeasurementsIonizing dose estimation