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© CEA Tous droits réservés. Toute reproduction totale ou partielle sur quelque support que ce soit ou utilisation du contenu de ce document est interdite sans lautorisation écrite préalable du CEA All rights reserved. Any reproduction in whole or in part on any medium or use of the information contained herein is prohibited without the prior written consent of CEA Detectors for Astronomy Workshop HgCdTe e-APDs at CEA/LETI - Johan Rothman APDs Advantages vs. Photo-multipliers or amplified-CCD High Quantum efficiency 100% All detection-modes are possible Photon-counting Real time measurement of the flux f(t) at high speed Integration (standard imaging operation) Non-linear geiger mode (avalanche breakdown) Small and fast Compatible with imaging and telecom applications …but furious (other than HgCdTe-APDs…) Multiplication of both electrons and holes in Si and III-V material APDs Gain is strongly dependent on junction profile High dispersion (not good for imaging) Strong degradation of the SNR: F=SNR SNL /SNR out >2-5 at M>10 Response time is slowed down at high gain Limited gain- Band-Width product < 340GHz (Intel record, Nature Photonics, 3, 2008) After pulsing probability >0 (photon counting) Dead time (photon counting)

© CEA Tous droits réservés. Toute reproduction totale ou partielle sur quelque support que ce soit ou utilisation du contenu de ce document est interdite sans lautorisation écrite préalable du CEA All rights reserved. Any reproduction in whole or in part on any medium or use of the information contained herein is prohibited without the prior written consent of CEA Detectors for Astronomy Workshop HgCdTe e-APDs at CEA/LETI - Johan Rothman Exclusive electron multiplication in HgCdTe APDs Exponential gain without avalanche break down (Beck,DRS, 2001) Exclusive electron multiplication F electric ~1-1.2 (DRS, SELEX, LETI, BAE, TELEDYNE) Response time independent of gain GBW>16THz (LETI) Low gain dispersion Noise equivalent input counts N eq_in < e/s (LETI, DRS) Stable up to M>5000 (LETI APD Record, 2006) PLUS all the standard properties of HgCdTe High quantum efficiency (close to 100% internal QE) Detect wavelengths from visible to IR (with QE~100%) Low operating temperatures due to small E g Gain M=I/I CC HgCdTe e-APD c =5µm, T=80K

© CEA Tous droits réservés. Toute reproduction totale ou partielle sur quelque support que ce soit ou utilisation du contenu de ce document est interdite sans lautorisation écrite préalable du CEA All rights reserved. Any reproduction in whole or in part on any medium or use of the information contained herein is prohibited without the prior written consent of CEA Detectors for Astronomy Workshop HgCdTe e-APDs at CEA/LETI - Johan Rothman A new horizon of applications from visible to IR wavelengths with MCT e-APDs :(M>1000, F~1, N eq_in < e/s) Photon counting Quantum optics Physics, astronomy, quantum cryptography Imaging in Astronomy, biomedical applications, high-energy physics Astronomy : higher order correlation functions! Real-time measurements Telecommunications Time resolved Raman and Fluorescence spectroscopy, Doppler effect Environmental surveillance, element recognition Real-time dynamics observations Integration (Imaging FPAs) Active laser assisted imaging Long range identification, safe planetary landing (NASA), bio-medical (fluorescence imaging), observation through semi transparent surfaces Passive amplified imaging Low flux applications ; hyper spectral imaging, wave front detection for astronomy, high dynamic range The geiger modes is not (yet) possible due to the absence of avalanche break-down threshold This talk (1) This talk (2)

© CEA Tous droits réservés. Toute reproduction totale ou partielle sur quelque support que ce soit ou utilisation du contenu de ce document est interdite sans lautorisation écrite préalable du CEA All rights reserved. Any reproduction in whole or in part on any medium or use of the information contained herein is prohibited without the prior written consent of CEA Detectors for Astronomy Workshop HgCdTe e-APDs at CEA/LETI - Johan Rothman Performance optimization of HgCdTe e- APDs? MW ( c =4.2-5µm) e-APD performances: M>100, F=1.2, I eq_in ~10000 e/s, t resp ~2 ns, T op <100K ApplicationPhoton counting M, F ok Passive amplified imaging M, F, t resp ok Critical parameter 1. Reduce t resp : <100 ps Reduce I eq_in : <1000 e/s (Operability) 1. Reduce I eq_in : < 1000 e/s 2. Increase T op (Operability) This talkE-APD gain (F~1) for photon counting Response time limits (jitter) Impact of x Cd : Gain, F, dark current (Diodes and FPAs)

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© CEA Tous droits réservés. Toute reproduction totale ou partielle sur quelque support que ce soit ou utilisation du contenu de ce document est interdite sans lautorisation écrite préalable du CEA All rights reserved. Any reproduction in whole or in part on any medium or use of the information contained herein is prohibited without the prior written consent of CEA Detectors for Astronomy Workshop HgCdTe e-APDs at CEA/LETI - Johan Rothman Exclusive electron multiplication for Linear mode proportional photon counting Low F Proportional photon counting Distinguish the number of photons that arrives simultaneously in the depletion layer (not possible in GM-APDs) Reduce after-pulsing effects 0% (GM –APDs ~10%) High order temporal correlation function A new window for astronomy ! No quenching high repetition rates >GHz is possible (GM- APDs ~ 10MHz) 1 photon 2 photons Output count probability distribution for =300 and F=1.04

© CEA Tous droits réservés. Toute reproduction totale ou partielle sur quelque support que ce soit ou utilisation du contenu de ce document est interdite sans lautorisation écrite préalable du CEA All rights reserved. Any reproduction in whole or in part on any medium or use of the information contained herein is prohibited without the prior written consent of CEA Detectors for Astronomy Workshop HgCdTe e-APDs at CEA/LETI - Johan Rothman Exclusive electron multiplication for Linear mode proportional photon counting Low F Proportional photon counting Reduce after-pulsing effects (GM –APDs ~10%) No quenching high repition rate >GHz is possible (GM-APDs ~ 10MHz) Low F Discrimination of non-amplified dark current Low DCR Depends on the distribution of the dark current generation Homogeneous distribution dark =52 for M diff =300 1 photon 2 photons Output count probability distribution for =300 and F=1.04 Distributed dark-current generation pin DC generation dark

© CEA Tous droits réservés. Toute reproduction totale ou partielle sur quelque support que ce soit ou utilisation du contenu de ce document est interdite sans lautorisation écrite préalable du CEA All rights reserved. Any reproduction in whole or in part on any medium or use of the information contained herein is prohibited without the prior written consent of CEA Detectors for Astronomy Workshop HgCdTe e-APDs at CEA/LETI - Johan Rothman Response time optimization in APDs n- n+ p Depletion layer = mutliplication region E Collection of minority electrons Diffusion ~ 1-5 ns 1 Drift (x Cd gradient) V d of e in p type HgCdTe ps jitter 3 Transit time of e and h V d (E) : t h =10-50ps GBW limit ~20THz (MW) 1,2 RC charge evacuation ~ ps Ultimate photon counting timing resolution <100ps! Collection of minority electrons Transit time of e and h RC charge evacuation 1.G. Perrais et al. JEM, 37, G. Perrais et al. JEM, 38, J. Rothman et al. to be published, JEM, 40 (2010) Response time jitter limits the timing precision

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© CEA Tous droits réservés. Toute reproduction totale ou partielle sur quelque support que ce soit ou utilisation du contenu de ce document est interdite sans lautorisation écrite préalable du CEA All rights reserved. Any reproduction in whole or in part on any medium or use of the information contained herein is prohibited without the prior written consent of CEA Detectors for Astronomy Workshop HgCdTe e-APDs at CEA/LETI - Johan Rothman Gain performance in e-APDs (x Cd ) c =5.3 µm LPE c =4.2 µm LPE c =3.3 µm MBE c =2.9 µm MBE c =2.9 µm MBE, larger depletion layer Exponential gain exclusive electron multiplication at M>600 for c =2.9 µm (T=80K) Hole multiplication is still negliable up to high gains at high x cd c =2.9µm is compatible with high operating temperature active laser imaging (I sat ~20pA in VHg doped MCT at T=200K) Gain is dependent on junction geometry also at c =2.9µm

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© CEA Tous droits réservés. Toute reproduction totale ou partielle sur quelque support que ce soit ou utilisation du contenu de ce document est interdite sans lautorisation écrite préalable du CEA All rights reserved. Any reproduction in whole or in part on any medium or use of the information contained herein is prohibited without the prior written consent of CEA Detectors for Astronomy Workshop HgCdTe e-APDs at CEA/LETI - Johan Rothman M 2D identification : C active =30fF (0.3Me, 90 e rms noise) Passive thermal surveillance C passive =120fF (1.2Me, 150 e rms noise) SpecificationExpected valueCompliance Max frame rate 450 Hz (10MHz, 4 outputs) C Linearity>99.7% from 0% to 90% of ROIC Well-fill C Mini Integration time / gating100 nsecC BloomingNo parasitic effectC Max diode reverse bias7 VC 320x256 30µm pitch MCT bi-mode e-APD FPA Success of DEFIR in 2009 (collaboration with Sofradir) MW e-APD, c =5.3µm à 80K TIA 3:rd demonstration of large format e-APD FPA for 2D imaging Selex (2004), DRS (2006), both with gain operability of 99%

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© CEA Tous droits réservés. Toute reproduction totale ou partielle sur quelque support que ce soit ou utilisation du contenu de ce document est interdite sans lautorisation écrite préalable du CEA All rights reserved. Any reproduction in whole or in part on any medium or use of the information contained herein is prohibited without the prior written consent of CEA Detectors for Astronomy Workshop HgCdTe e-APDs at CEA/LETI - Johan Rothman 320x256 MW HgCdTe e-APD c =5.4 µm, T=80 K (Narrow multiplication layer tunneling) BiasMI eq_in (A)I obs (A) dark cont_gen E-154.0E E-147.5E E-147.0E Flux (BB at T=290K) FOV=0° + Photon leakage Zero flux I eq_in 3.5V, M=10, C1=120fF, t int =40ms I eq_in =10 fA (60 ke/s) 4.5V, M=25, C1=120fF, t int =300µs I eq_in =70 fA (420 ke/s) dark cont_gen. for M>10: Dark current can be suppressed using photon counting thresholding

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© CEA Tous droits réservés. Toute reproduction totale ou partielle sur quelque support que ce soit ou utilisation du contenu de ce document est interdite sans lautorisation écrite préalable du CEA All rights reserved. Any reproduction in whole or in part on any medium or use of the information contained herein is prohibited without the prior written consent of CEA Detectors for Astronomy Workshop HgCdTe e-APDs at CEA/LETI - Johan Rothman LETI/Sofradir HgCdTe e-APD Road-map Exclusive electron multiplication HgCdTe APDs Q2 2D Active/passive FPA 320x256, p30µm Q3 3D Active FPA 320x256, p30µm Wavefront/Fringe tracking 320x256, > 1.5kFPS, noise < 2 e- photon counting Single element Photon counting array Format to be defined Q4 Real time BW>GHz Single element Q3 2D TOF imaging 320x256, p30µm Optimizing HgCdTe e-APDs Operability >99.9%, low dark noise (10 e-/s), speed (<100ps) Develop dedicated proximity electronics to address a maximum of applications (RON < 1 e-)

© CEA Tous droits réservés. Toute reproduction totale ou partielle sur quelque support que ce soit ou utilisation du contenu de ce document est interdite sans lautorisation écrite préalable du CEA All rights reserved. Any reproduction in whole or in part on any medium or use of the information contained herein is prohibited without the prior written consent of CEA Detectors for Astronomy Workshop HgCdTe e-APDs at CEA/LETI - Johan Rothman Conclusions/Perspectives MCT e-APDs F~1 at M>600 for c =2.9 µm to 5.4 µm at T=80K Linear mode photon counting Proportional counting (detect 1, 2.. photons) Discriminate non-amplified dark currents Low DCR Timing precision below 100 ps No after pulsing is expected ROIC (CMOS)-design is the key to harnest the potential of MCT e-APDs 2D active imaging array N eq_in <12 e-/s in c =2.9 µm array at M=25 enables wave front sensing 3D AI array under testing : timing precision~1ns (15cm) 2010 Low noise-high speed wave front sensor N eq_in 10 Single element photon counting