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Radiation tolerance of a Monolithic Active Pixel Sensor with High Resistivity Epitaxial Layer Dennis Doering, Goethe University Frankfurt am Main on behalf of the CBM-MVD- Collaboration. O utline Operation principle of MAPS MAPS with High Resistivity Epitaxial Layer
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Radiation toleranceof a MonolithicActive Pixel Sensor with High ResistivityEpitaxial Layer Dennis Doering, Goethe University Frankfurt am Main on behalf ofthe CBM-MVD-Collaboration • Outline • Operation principleof MAPS • MAPS with High ResistivityEpitaxial Layer • Radiation hardnessstudies • Resultsfrom CERN beam test • Conclusion
The CBM Micro Vertex Detector based on CMOS sensors The CBM-experiment (at FAIR) Expected radiation dose @MVD of CBM Expected radiation dose per CBM running-year: How to develop a CMOS sensor which can tolerate such non-ionizing radiation doses? Dennis Doering: Mimosa26: Radiation hardness studies DPG Münster HK 13.5 March 2011
Operation principle N+ SiO2 SiO2 SiO2 P-Well N+ P+ Diode MIP P- Epitaxial Layer Substrate P+ e- e- Dennis Doering: Mimosa26: Radiation hardness studies DPG Münster HK 13.5 March 2011
Charge spectrum N+ SiO2 SiO2 SiO2 Photon P-Well N+ P+ Diode P- Epitaxial Layer Substrate P+ e- e- e- e- Dennis Doering: Mimosa26: Radiation hardness studies DPG Münster HK 13.5 March 2011
MIMOSA-26 Analog output (8 parallel columns) Pixel array: 1152*576 pixel Pitch 18.4 µm Integration time <100µs Zero suppressionlogic digital output Twoversions: Standard (13 Ω cm; NA≈1015 cm-3) High Resistivity (400 Ω cm; NA≈1013 cm-3) Dennis Doering: Mimosa26: Radiation hardness studies DPG Münster HK 13.5 March 2011
High resistivity Gerhard Lutz Semiconductor Radiation Detectors Page 43 (3.1.5) Size ofthe depletedzone Doping concentration • Idea: Decreasingthedopingconcentrationfrom 1015to 1013shouldincreasethesizeofthedepletedzone: • Improvedperformanceexpected due to an extendedregionof a 100% CCE. Dennis Doering: Mimosa26: Radiation hardness studies DPG Münster HK 13.5 March 2011
Charge Collection Efficiency C: 100% CCE A: Moderate CCE Unexpected (featureof MIMOSA-26) Perhapslowdepletionvoltage (0.7V) B: Advanced CCE Dennis Doering: Mimosa26: Radiation hardness studies DPG Münster HK 13.5 March 2011
MIMOSA-18 AHR Charge Collection Efficiency Preliminary As expected 2.5V C: 100% CCE A: Moderate CCE Unexpected (featureof MIMOSA-26) Perhapslowdepletionvoltage (0.7V) B: Advanced CCE Dennis Doering: Mimosa26: Radiation hardness studies DPG Münster HK 13.5 March 2011
Charge spectrum after non-ionizingirradiation Dennis Doering: Mimosa26: Radiation hardness studies DPG Münster HK 13.5 March 2011
Charge spectrum after non-ionizingirradiation The same chargecollectionefficiencyfor theirradiated High Resistivitysensorasfor theunirradiated Standard sensor. Dennis Doering: Mimosa26: Radiation hardness studies DPG Münster HK 13.5 March 2011
Noise Preliminary High Resistivity ⇒ highernoise. T=+20°C: Increasingwithradiation dose. Dennis Doering: Mimosa26: Radiation hardness studies DPG Münster HK 13.5 March 2011
Noise Preliminary Preliminary • High Resistivity ⇒ highernoise. • T=+20°C: Increasingwithradiation dose. • T=-20°C: Slightlyincreasing/constantaround 14e. • Goodnoiseperformancedespiteofradiation. Dennis Doering: Mimosa26: Radiation hardness studies DPG Münster HK 13.5 March 2011
Beam test @ CERN by IPHC Strasbourg Preliminary Preliminary Irradiated High Resistivitysensor: Betterefficiencythanunirradiated Standard sensor. Fakehit rate remainsunchanged. Dennis Doering: Mimosa26: Radiation hardness studies DPG Münster HK 13.5 March 2011
CMOS-MAPS sensors with High Resistivity MIMOSA-26 radiationhardnessstudieswereperformed. High Resistivity MIMOSA-26 aremoreradiationhardthan Standard sensors. Radiation toleranceagainst >1013neq/cm² achieved. Beam test: Efficiency ofirradiated High Resistivitysensorsis still betterthanoftheunirradiated Standard sensors. Summary • How to develop a CMOS sensor which can tolerate such non-ionizing radiation doses? • High Resistivity in CMOS-MAPS! Dennis Doering: Mimosa26: Radiation hardness studies DPG Münster HK 13.5 March 2011