Complete suppression of reverse annealing in neutron irradiated MCZ - PowerPoint PPT Presentation

Complete suppression of reverse annealing in neutron irradiated MCZ Si detectors during gamma irradiation Z. Li, W. Chen, R. Gul, J. Kierstead Brookhaven National laboratory, USA E. Verbitskaya, V. Eremin Ioffe Physical-Technical Institute of Russian Academy of Sciences St. Petersburg, Russia J. Härkönen Helsinki Institute of Physics, Finland M. Hoeferkamp, J. Metcalfe, S. Seidel University of New Mexico, Albuquerque, USA 8th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors, Taipei, Taiwan; Sunday 04 December 2011 - 1 Thursday 08 December 2011

Outline • Background • Experimental • I-V characteristics • Current pulse response • Reverse annealing suppression by gamma Conclusions 2 Z. Li et al., 8th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors, Taipei, Taiwan; 12/04-08/2011

Background Goal of the study Develop radiation hard Si detector that can utilize mixed irradiation in ILC: gamma + electrons + neutrons Task ⇒ compensation of donor-type and acceptor-type defects The task of mixed irradiation is also important for LHC 3 Z. Li et al., 8th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors, Taipei, Taiwan; 12/04-08/2011

Experimental Samples: p + -n-n + Si detectors processed in BNL n-type MCZ Si, ρ ~ 1 k, d = 390 µm Characterization (all done at BNL) :  I-V, C-V  TCT with red laser  I-DLTS with infrared laser filling 4 Z. Li et al., 8th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors, Taipei, Taiwan; 12/04-08/2011

Irradiation and annealing Neutrons: Research Reactor in Sandia National Lab, 0.8-1 MeV, Hardness Factor is 1.3), F n up to 3x10 14 n eq /cm 2 Gamma: BNL’s 60 Co Radiation facility (1.25 MeV), to a total dose of 500 Mrad n RTA + γ on two det. RTA 1 2 3 time 22 days 36.5 month 5.5 month Sample # 1480-13 1480-5 1480-14 1480-16 1 st irradiation, 1.5x10 14 1.5x10 14 3x10 14 3x10 14 n eq /cm 2 2 nd irradiation, 0 500 0 500 gamma (Mrad) 5 Z. Li et al., 8th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors, Taipei, Taiwan; 12/04-08/2011

I-V characteristics: influence of gamma RTA only Gamma during 5.5 month 10 -3 10 -3 1480-5 22 days 1480-13 22 days 5.5 m 5.5 m 12 m 12 m 36.5 m 10 -4 36.5 m 10 -4 current (A) current (A) 10 -5 10 -5 10 -6 10 -6 1 10 100 1 10 100 bias voltage (V) bias voltage (V) #1480-5: I-V did not change during gamma irradiation 6 Z. Li et al., 8th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors, Taipei, Taiwan; 12/04-08/2011

TCT: Transient Current Technique 0.025 #798-89, 5k, 400um, p+ side, 80 V, 1.19E13p/cm2, 0.01 Before radiation 200MeV, 4d RTA #798-89, 5k, 400um, n+ side, 80 V, Before radiation 0.02 1.19E13p/cm2, 200MeV, 4d RTA 0.008 0.015 0.006 i (uA ) i (uA ) 0.004 0.01 0.002 0.005 0 0 0.0E+00 5.0E-08 1.0E-07 1.5E-07 2.0E-07 2.5E-07 4.0E-08 5.0E-08 6.0E-08 7.0E-08 8.0E-08 9.0E-08 1.0E-07 Time (s) Time (s) Laser illumination on the Ohmic side Laser illumination on the junction side (n + -side) (p + -side) Red laser induced current shapes Red laser follow the shape of E-field Red laser 5 um absorption in Si 5 um absorption in Si E E e p + n + h n + n 7 p + n

Current pulse response Neutrons only # 1480-13, F n = 1.5x10 14 cm -2 RTA 22 days (1 st interval, end) electrons holes n + p + -SC (SCSI)/DJ V fd = 187 V p + n + 384 V 237 V 187 V 286 V 140 V 237 V 90 V 187 V 140 V 90 V V fd from C-V RTA, 5.5 m (2 nd int., end) Electron transient After RT reverse anneal 412 V 354 V 315 V 286 V 168 V 8 Z. Li et al., 8th International "Hiroshima" Symposium on the Development and Application of V fd Semiconductor Tracking Detectors, Taipei, Taiwan; 12/04-08/2011

Current pulse response: impact of gamma #1480-5, 1.5x10 14 n/cm 2 + 500 Mrad (lower F n ) Just after neutrons (1 st int., end) 5.5 m RTA + gamma: 2 nd int., end Before gamma and RT reverse anneal After gamma and RT 177 V reverse anneal 167 V 158 V 160 V 148 V 140 V 130 V 138 V 91 V V fd from C-V V fd (CV) Pulse shapes and V fd are similar 9 Z. Li et al., 8th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors, Taipei, Taiwan; 12/04-08/2011

Current pulse response: impact of gamma 1480-16, 3x10 14 n/cm 2 +500 Mrad gamma (5.5 month RT anneal), #1480-16, 3x10 14 cm -2 + 500 Mrad (higher F n ) MCZ n-type Si, p + /n/n + structure + to n + Laser front, electron current from p Double junction, and SCSI seen RTA 5.5 m After gamma and RT Before gamma and RT reverse anneal reverse anneal 645 V 600 V 645 V 554 V 600 V 508 V 554 V 508 V 460 V 460 V V fd V fd Pulse shapes and V fd are also similar 10 Z. Li et al., 8th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors, Taipei, Taiwan; 12/04-08/2011

Current pulse response: 36.5 month RTA Lower F n 3 rd interval, end, RTA 36.5 months 0.06 0.015 1480-5 1480-13 307 V 0.04 431 V 0.01 s ig nal (V) signal (V) 365 V 568 V 640 V 402 V 675 V 460 V 742 V 0.02 618 V 0.005 0 0 -10 0 10 20 30 40 50 60 70 80 -10 0 10 20 30 40 time (ns ) time (ns) 1.2 1480-13; 1.4e14 Q normalized (arb. units ) DP pulse shape arises at lower V n/cm2 1 1480-5; 1.5e14 n/cm2 + 500 Mrd in detector irradiated by gamma 0.8 and is more pronounced 0.6 0.4 0.2 0 0 200 400 600 800 1000 bias v oltag e (V) 11 Z. Li et al., 8th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors, Taipei, Taiwan; 12/04-08/2011

Current pulse response and collected charge: 36.5 month RTA Higher F n Collected charge 3 rd interval, end 0.01 566 V 6.E -10 1480-16 702 V 1480-13, 1.5e14 n/cm2 gamma 0.008 787 V 5.E -10 collected charge (Vs) 1480-5, 1.5e14 n/cm2 + 810 V 500 Mrd 862 V 1480-14, 3e14 n/cm2 signal (V) 0.006 4.E -10 1480-16, 3e14 n/cm2 + 500 Mrd 3.E -10 0.004 2.E -10 0.002 1.E -10 0 -10 0 10 20 30 40 50 60 0.E +00 time (ns) 0 200 400 600 800 1000 bias voltage (V) DP and full depletion only in detector # 1480-16 irradiated by In detectors irradiated by gamma: gamma  Q saturation whereas for # 1480-14 (no  lower V fd gamma) from p + side only small electron pulses 12 Z. Li et al., 8th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors, Taipei, Taiwan; 12/04-08/2011

Evolution of V fd and N eff vs. RTA Reverse anneal resumes with similar rate Reverse anneal suppression γ -dose after neutron F n (n eq /cm 2 ) Changes in N eff Reverse annealing +SC would have suppression been generated irradiation during 5.5 m during 5.5 m RTA Reverse anneal with gamma- RTA (Mrad) (cm -3 ) radiation alone resumes even in gamma-irradiated 1.5x10 14 500 +0.1x10 12 completely +1.5x10 12 detectors when 3x10 14 500 ~0 completely +1.5x10 12 gamma irrd. stops 1.5x10 14 0 -1.8x10 12 no 3x10 14 0 -4.7x10 12 no 13 Z. Li et al., 8th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors, Taipei, Taiwan; 12/04-08/2011

I-DLTS spectra RTA 5.5 months 1480-5, neutrons + gamma 1480-13, only neutrons 100 K: A-center 5.5 m RTA: 1480-13 P 100 /P 300 = 0.36 200-300 K: 1480-5 P 100 /P 300 = 0.87 V -- + cluster defects 14 Z. Li et al., 8th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors, Taipei, Taiwan; 12/04-08/2011

Conclusions In mixed irradiation neutrons + gamma: • Complete suppression of reverse annealing occurs only during gamma irradiation, and disappears when gamma stops, and reverse anneal resumes with similar rate 2. Suppression is independent on applied F n 3. Interaction of different defects? 4. DP/DJ effects are observed also for mixed irradiation 15 Z. Li et al., 8th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors, Taipei, Taiwan; 12/04-08/2011

Acknowledgments This work was made in the framework of RD50 collaboration and supported in part by: • U.S. Department of Energy, Contract No. DE-AC02 -98CH10886, • Fundamental Program of Russian Academy of Sciences on collaboration with CERN, • RF President Grant # SS-3306.2010.2 Thank you for attention! 16 Z. Li et al., 8th International "Hiroshima" Symposium on the Development and Application of Semiconductor Tracking Detectors, Taipei, Taiwan; 12/04-08/2011