1. 1/14 Characterization of P-type Silicon Detectors Irradiated with Neutrons M.Miñano 1, J.P.Balbuena 2, C. García 1, S.González 1, C.Lacasta 1, V.Lacuesta 1, M.Lozano 2, S. Martí i García 1, G. Pellegrini 2,3, M. Ullán 2 (1) Instituto de Física Corpuscular, IFIC (CSIC-UVEG), Valencia, Spain (2) Instituto de Microelectrónica de Barcelona, CNM-IMB (CSIC), Bellaterra, Spain (3) Departamento de Electrónica, Informática y Automática, Universidad de Gerona, Spain 3rd Workshop on Advanced Silicon Radiation Detectors, Barcelona, Spain 14 April 2008

2. 2/14 Outline I. Fabrication process II. P-type  strip detectors irradiated with neutrons III. Setup (Laser & Radiactive Source) IV. I-V results V. Q-V results VI. Summary and Outlook

3. 3/14 I. Fabrication Process  Detectors have been fabricated in the Clean Room facility of CNM-IMB  Rd50 Mask  Designed by the RD50 Collaboration  Double side processing  One metal layer  Structures  26 microstrips detectors  Polysilicon biasing resistors  Capacitive coupling  P-spray insulation  No p-stops  20 pad detectors  12 pixel detectors  8 test structure sets

4. 4/14 II. P-type  strip detectors irradiated with neutrons  1 MeV equivalent neutron irradiation at TRIGA nuclear reactor in Ljubljana, Slovenia. FLUENCES 1X10 14 n/cm 2 3x10 14 n/cm 2 1x10 15 n/cm 2 3x10 15 n/cm 2 8x10 15 n/cm 2 Area: 1x1 cm 2 130 strips, width: 32  m Pitch: 80  m Thickness: 300  m Multiple guard ring Surface isolation: p-spray Wire bonding  No annealing  DOFZ, MCz substrates to evaluate

5. 5/14 III. Laser Setup Laser strip sensor Trigger Signal Horizontal scale 20mV 1V Real signal viewed at 70V in the scope  Laser light is generated by exciting a laser source with an external pulsed signal (2 V and 1 MHz rate) Laser properties:  =1060 nm (Near Infrared)  Laser energy of photons=1.170 eV

6. 6/14 III. Radiactive Source Setup 90 Sr strip sensor Signal Trigger Horizontal scale Photomultiplier 200 mV /div 2 mV /div Real signal viewed at 300V in the scope  Measurements are used to calibrate the laser measurements  - source

7. 7/14 Laser Oscilloscope Faraday Cage Photomultiplier and Scintillator Power Supply PM power supply freezer Sensor cage  Source

8. 8/14 IV. Current vs Voltage: DOFZ  T = -40 o C For the sensor irradiated with 1x10 14 n/cm 2 we observed an extremely early break

9. 9/14 IV. Current vs Voltage: MCz  T = -40 o C

10. 10/14 V. Charge vs Voltage: DOFZ  T = -40 o C

11. 11/14 V. Charge vs Voltage: MCz  T = -40 o C Global warming? Effect due to high current level? Systematic error?

12. 12/14 Neutron Irradiation: Comparison DOFZ vs MCz substrates at the same fluences Non-irradiated 3 x 10 14 n eq /cm 2 1 x 10 15 n eq /cm 2

13. 13/14 Degradation after neutron irradiation: Q-  V=500V Collected charge is unaffected by the silicon substrate type

14. 14/14 VI. Summary and Outlook  P-type  strip sensors have been fabricated in CNM-IMB and irradiated with neutrons at several fluences at the TRIGA Nuclear Reactor in Ljubljana.  Detectors on alternative substrates (MCz, DOFZ) have been evaluated.  Current and Collected charge vs Voltage measurements have been done.  Even after the highest neutron fluence (equivalent to 10 years of the sLHC operation) the detectors are still operational. For instance, at 8.0 10 15 n/cm 2 ~7300 e- are collected at 900V.  MCz charge collection at high bias voltages to be understood.  The neutron radiation hardness does not depend on the substrate technology.  Near future plans, ALIBAVA system will be used to performance the charge collection measurements and signal characterization.  More neutron and proton irradiated detectores will be characterized in the coming months.