News from APD screening @ 08.06.2016 Andrea Wilms GSI Darmstadt - - PowerPoint PPT Presentation

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news from apd screening

News from APD screening @ 08.06.2016 Andrea Wilms GSI Darmstadt - - PowerPoint PPT Presentation

Dec 24, 2023 428 likes •566 views

@ News from APD screening @ 08.06.2016 Andrea Wilms GSI Darmstadt PANDA EMC Meeting June 2016 Capacitance measurements @ What couldcapacitance measurements be used for? Determination ofCapacitance @ M = 50 (Quality Assurance)

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News from APD screening @

08.06.2016 Andrea Wilms – GSI Darmstadt – PANDA EMC Meeting June 2016

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Capacitance measurements

08.06.2016 Andrea Wilms – GSI Darmstadt – PANDA EMC Meeting June 2016

What couldcapacitance measurements be used for?

Ø Determination ofCapacitance @ M = 50 (Quality Assurance) Ø Determination offull depletion voltage UFD Ø (Verification of breakdown condition(UBr ) given by manufacturer: Ubr ≝ Ubias @ Id = 100 mA) Ø Extraction ofdopingprofile

Technical specificationsat 20 °C:

max. Terminal capacitance @ M = 50 and with f = 100 kHz: C ≤ 270 pF

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08.06.2016 Andrea Wilms – GSI Darmstadt – PANDA EMC Meeting June 2016

Capacitance measurements

Different Ubr values

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08.06.2016 Andrea Wilms – GSI Darmstadt – PANDA EMC Meeting June 2016

Capacitance measurements

Cj =

#$(&) ()(*+,-. *+, ⁄ )

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08.06.2016 Andrea Wilms – GSI Darmstadt – PANDA EMC Meeting June 2016

Capacitance measurements

Bias voltage area used

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08.06.2016 Andrea Wilms – GSI Darmstadt – PANDA EMC Meeting June 2016

Full depletion

Figure 7

Two different methods ofAPD gain determination (without using radioactive sources) are possible: continous and pulsed light illumination We knowalready: A reference value for gain normalization between these two methods is needed

Therefore: The individual full depletion voltage of each APD should be used as reference point for this investigation.

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08.06.2016 Andrea Wilms – GSI Darmstadt – PANDA EMC Meeting June 2016

Full depletion

UFD

Start of full depletion plateau @ Capacitance Ratios ≥ 0.9995

Determination of full depletionvoltage UFD

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08.06.2016 Andrea Wilms – GSI Darmstadt – PANDA EMC Meeting June 2016

Full depletion

194 APD samples measured so far

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08.06.2016 Andrea Wilms – GSI Darmstadt – PANDA EMC Meeting June 2016

Full depletion

SN 1305103897 SN 1703018749 SN 1715019518 APD outside specs, reached us by accident, not part of delivery All of them inside techn. specs. „Ground“ bonding:

„Usual“ behaviour „Unusual“ behaviour

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08.06.2016 Andrea Wilms – GSI Darmstadt – PANDA EMC Meeting June 2016

Doping profile

N ~ #12.3.

5(6 78 ⁄ ) 59

𝜖(1 𝐷2 ⁄ ) 𝜖𝑉

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08.06.2016 Andrea Wilms – GSI Darmstadt – PANDA EMC Meeting June 2016

Doping profile

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08.06.2016 Andrea Wilms – GSI Darmstadt – PANDA EMC Meeting June 2016

Summary: Ø Capacitance measurements ongoing (Lot 07-Lot 17 finished) Ø ALL Capacitances measured so far are inside techn. specs. Ø Unusual behaviour of individual APDs above Breakdown under investigation Ø Capacitance variances inside regime of operation in the order of ± 2 % Ø Full depletionvoltages determinedin addition: Mean value at ~370 V (using a fixed boundary conditionfor the capacitance ratio) Ø Doping profiles extracted for each APD passing the Capacitance determinationcycle (~ 200 doping profiles available) Ø Doping profiles in very good agreement with CMS APD: nearly identical internal structure Ø overall screening status: further ~6000 APDs pre-validated @ T = -25 °C -> in pipe for final validation, all APDs (with available MoU) passed the first screening cycle, MoU with Mainz signed last month