17th RD50 Workshop (CERN)

17 Nov 2010, 13:30 → 19 Nov 2010, 16:30 Europe/Zurich

503/1-001 - Council Chamber (CERN)

Michael Moll (CERN)

17th RD50 Workshop on Radiation hard semiconductor devices for very high luminosity colliders

Wednesday 17 November

13:30 → 13:50 Welcome

Convener: Michael Moll

13:30 Welcome to Workshop

Speakers: Gianluigi Casse (Department of Physics), Michael Moll (CERN)

Slides 101117-Intro-Michael-Moll.pdf 101117-Intro-Michael-Moll.ppt

13:50 → 17:00 Defect and Material Characterization

Convener: Prof. Mara Bruzzi (INFN and University of Florence)

13:50 Optical studies of defect centers formed in MCz-Si and FZ-Si by high-fluence neutron irradiation

Photoluminescence (PL) and infrared absorption (IRA) techniques have been applied to study defect centers formed in MCz and FZ by high-fluence neutron irradiation. The MCz-Si and FZ-Si samples prepared by the WODEAN group were irradiated with neutron fluences ranging from 1x10^14 to 3x10^16 cm^-2. The studies were performed in a temperature range of 13 K–100 K using both the as-irradiated and subjected to isochronal annealing samples. The annealing temperature ranged from 300 to 780 K and the time was 1 h or 0.5 h. The PL measurements were mainly concentrated on the intensity changes of the W (I3) and I4 lines, commonly assumed to be related to complexes built of tri- and four- silicon interstitial atoms, respectively. Temperature dependence for the W line intensity was measured in a temperature range of 13–110 K. The quenching process energy for the W line was found to be 0.3 eV, what is closed to the activation energy for vacancy diffusion. Assuming that W-line is a tri-interstitial complex (I3), this could suggest that the annihilation of the W-line at 1.018 eV is due to vacancy - interstitial recombination process. From the Arrhenius plot for the I4 line, •the activation energy for increasing the I4 line (1.039 eV) intensity was found to be nearly the same as that for decreasing the W line (1.018 eV) intensity and was equal to (0.75 +/- 0.15) eV only in a very narrow temperature range. This would suggest that the tri-interstitials can be the precursors for the formation of I4 centres in this temperature range. The IRA measurements were focused on the study of the absorption coefficient related to the divacancy (V2) in neutral and negatively charged states. From these measurements, the concentrations of V2(0) and V2(-) for various neutron fluences were determined and the rates of their formation have been found to be 0.3 cm^-1 and 0.13 cm^-1, respectively.

Speaker: Barbara Surma (Institute of Electronic Materials Technology)

Slides Surma-Geneva_2010_new_15-11_2010.pdf Surma-Geneva_2010_new_15-11_2010.ppt

14:10 New results on the annealing behaviour of the E4/E5-defect

This work deals with the bistable congurations of the E4/E5-defect levels, which are known to be the important current generator after neutrons and charged hadrons irradiation. We studied 300 um thick n-type diodes made from MCz and FZ-silicon after irradiation with reactor neutrons. Capacitance-Deep Level Transient Spectroscopy (C-DLTS) as well as Capacitance- Voltage and Current-Voltage characteristics were performed. E4/E5 is visible in C-DLTS directly after irradiation and anneals out at 80 °C by changing its configuration. The injection of high forward current reestablishes the E4/E5-conguration, even after high annealing temperatures (e.g. 200 °C). The aim of this study is to obtain optimal parameters for future studies of the E4/E5-defect. For this reason injection temperature, type of injected charge carriers, duration and value of applied current pulse were varied.

Speaker: Alexandra Junkes (Universität Hamburg)

Slides RD50junkes.pdf

14:30 TCAD simulation of Si crystal with different clusters.

The TCAD Synopsis program was used for: 1) investigation of electric field distribution in Si crystal containing different types and concentration of clusters; 2) analysis of dynamics of electric field around the cluster during and after excitation by a short light pulse. An aim of presentation is an attraction of proposals to model the behavior of semiconductor in other situations.

Speaker: Prof. Juozas Vaitkus (Vilnius University)

Slides Vaitkus-RD50-TCAD-clusters.pdf Vaitkus-RD50-TCAD-clusters.ppt

14:50 Properties of a new series of Hamamatsu Si diodes

A new series of diodes FZ-Si (Hamamatsu) investigated by: 1) a standar technique (I(V) and C(V)); 2) by microwave photoconductivity decay measurement; 3) the response on the linear front bias pulse technique (BELIV); 4) the photoconductivity specra in the extrinsic region. Measurements performed at room a tat low temperature. The results are compared with the similar measurements in other supplier and in irradiated samples.

Speaker: Prof. Juozas Vaitkus (Vilnius University)

Slides Vaitkus-rd50-Hamamtsu.pdf Vaitkus-rd50-Hamamtsu.ppt

15:10 Annealing Effects on Depletion Voltage and Capacitance of Float Zone and Magnetic Czochralski Silicon Diodes After 800 MeV Proton Exposure

The radiation damage effects on p- and n-type Float Zone (FZ) and Magnetic Czochralski (MCz) Silicon diodes were characterized by studying the capacitance and depletion voltage. The diodes were exposed to 800 MeV protons to fluences up to $1.5x10^{15}$ p/cm^2. The diodes were then annealed at 60 °C and measured at various intervals up to 1,000 minutes. The intent of this study is to understand the transition from reverse annealing to beneficial annealing where charge type inversion occurs to fully characterize the annealing behavior of the diodes. We compare the results to data from previous studies taken under different irradiation conditions and to theoretical models.

Speaker: Dr Konstantin Toms (University of New Mexico)

Slides RD50_ktoms.pdf

15:30 Coffee Break

16:00 Reverse current of heavily irradiated silicon detectors operated in the avalanche mode

The high concentration of radiation induced defects in the detector bulk is the key factor of detector parameters stabilization at very high biase voltage. In this presentation the effect of deep levels on the detector reverse current is considered and the calculated I-V characteristics are compared with the experimental ones.

Speaker: Vladimir Eremin

Slides Reverse_current_at_avalance_-_Vladimir_Eremin.pdf Reverse_current_at_avalance_-_Vladimir_Eremin.ppt

16:20 Discussion on Defect and Material Characterization and Pad Detector Characterization

Speakers: Eckhart Fretwurst (II. Institut fuer Experimentalphysik), Prof. Mara Bruzzi (INFN and University of Florence)

Slides discussion_DMC_171110.pdf discussion_DMC_171110.ppt

17:00 → 19:00 Collaboration Board Meeting

Closed Session

Convener: Eckhart Fretwurst (II. Institut fuer Experimentalphysik)

Thursday 18 November

09:00 → 16:00 Development and Characterization of Strip and Pixel Sensors

Convener: Gregor Kramberger (Jozef Stefan Institute)

09:00 Annealing effects in n+p strip detectors irradiated with high neutron fluences

Miniature p-type strip detectors were irradiated with reactor neutrons to fluences in the range from 2e14 neq/cm2 to 5e15 neq/cm2. Collected charge was measured with signals caused by fast electrons from Sr90 source and read out by SCT128A chip. Collected charge and leakage current was measured up to high bias voltages (1400 V) at which signs of charge multiplication can be observed. Detectors were submitted to successive annealing steps at 60°C up to total time of 5040 minutes. Increase of collected charge after long annealing times was measured at high bias voltages. A similar effect was observed in the leakage current, which at high voltages increased with reverse-annealing time.

Speaker: Igor Mandic (University of Ljubljana)

Slides Mandic_RD50_CERN_10.pdf Mandic_RD50_CERN_10.pptx

09:20 Room temperature annealing of the CCE in p-type Si sensors

Set of annealing measurements taken after ~ 200 days annealing at room temperature

Speaker: Dr Gianluigi Casse (Department of Physics)

Slides talk-RD50.pdf talk-RD50.pptx

09:40 Annealing CCE study on HPK FZ p-on-n ministrip detectors.

HPK FZ p-on-n ministrip detectors, of the type currently used in several LHC experiments, have been irradiated both with protons and neutrons to equivalent fluences of 1e15 n/cm^2. The detectors have then been characterized with beta CCE measurements based on the ALIBAVA system throughout several annealing steps, to assess the effect on the performances of the detectors of hypothetical long shutdowns of the cooling systems of the experiments.

Speaker: Mr Christopher Lucas (University of Bristol (UK))

Slides chis_17thrd50.pdf chis_17thrd50.pptx

10:00 Annealing study of a high irradiated FZ CMS mini sensor with the alibava setup

With the fully operational ALiBaVa setup at Karlsruhe an annealing study of a standard CMS mini sensor (FZ, n-type) was performed. The chosen fluence of 7.5e14 Neq/cm2 lies well above expectation for strip sensors after 300fb-1 at LHC and allows exploring the performance at even higher fluence, e.g. due to higher integrated luminosity before replacement of the strip Tracker or as material for S-LHC down to a radius of about 45cm. The focus of this study is on measured signal and signal to noise ratio. The sensor was not only run in reverse bias mode but with forward bias too, where we had a closer look at current and noise annealing.

Speaker: Robert Eber (Institut für Experimentelle Kernphysik, KIT)

Slides 2010_RD50_Alibava.pptx 2010_RD50_Robert_EBER.pdf

10:20 Edge-TCT measurements of heavily irradiated HPK p-type sensors

HPK p-type sensor was irradiated in steps with reactor neutrons up to the fluence of 1e16 cm-2. After each step several Edge-TCT measurements were performed during initial stage of annealing. Charge collection properties, drift velocity profiles were investigated as a function of annealing, fluence and bias voltage.

Speaker: Gregor Kramberger (Jozef Stefan Institute)

Slides Kramberger_Edge-TCT.pdf Kramberger_Edge-TCT.pptx

10:40 Coffee Break

11:10 AC—coupled pitch adapters for silicon strip detectors

Silicon strip detector modules that are used in tracker systems of high energy physics experiments consists of readout hybrid board, the sensor itself and pitch adapter (PA) in between hybrid and sensor. Modern strip detectors are almost exclusively AC-coupled because of high leakage current due to the harsh radiation environment. The AC-coupling requires resistive isolation of implanted strips from the DC-biasing circuit. Strip isolation is commonly realized by integrated poly-silicon bias resistors, where the resistance value is typically around 1M Ω. We present a novel approach for implementing the AC-coupling in the pitch adapter. AC-coupled PA's have been processed on ordinary glass glass wafers. The two layer fan metallization is aluminum and the intermediate capacitor insulator is aluminum oxide (Al2O3) deposited by the Atomic Layer Deposition (ALD) method. ALD is self-limiting Chemical Vapor Deposition (CVD) process, which characteristically results in pinhole-free thin films. The temperature of ALD Al2O3 deposition is 300^0C, thus it is appropriate for standard glass wafers, which are limited to about 400^0C in process steps. The bias resistors are made on the glass wafer by sputtering tungsten nitride (WNx). The deposition of WNx takes place at approximately room temperature and the resistors are patterned by wet etching with hydrogen peroxide. The electrical characterization of AC-coupled PA's indicate very good breakdown performance of the Al2O3 capacitors and homogeneity of WNx resistance values. A DC-coupled n+/p-/p+ strip detector made of p-type Fz-Si and irradiated with protons to a fluence of 3×10^14 neq/cm2 was attached to the CMS APV readout hybrid with an AC-coupled PA. The strip detectors size is 4cm × 4cm and it has 768 strips. Our test beam results indicate a signal-to-noise ratio of 27 for this module.

Speaker: Jasu Haerkoenen (Helsinki Institute of Physics HIP)

Slides Jaakko_Härkönen_17th_RD50_talk_AC_adapters.odp Jaakko_Härkönen_17th_RD50_talk_AC_adapters.pdf

11:30 Fabrication of new p-type strip detectors with trench to enhance the charge multiplication effect in the n-type electrodes.

The project aims to fabricate and fully characterize p-type strip detectors with trench electrodes to enhance the charge multiplication effect in the irradiated devices.

Speaker: Dr Giulio Pellegrini (Centro Nacional de Microelectronica CNM-IMB-CSIC)

Slides RD50_trenched.pdf RD50_trenched.pptx

11:50 Investigation of Punch-through Protection (PTP)

We checked the effectiveness of PTP structures against large deposits of ionization in the detector bulk using an IR laser, and compared it with the results of commonly used DC i-V measurements.

Speaker: Prof. Hartmut Sadrozinski (SCIPP, UC santa Cruz)

Slides RD50_PTP.pdf RD50_PTP.ppt

12:10 Lunch Break

13:40 A novel two-dimensional microstrip sensor with charge division readout

A novel microstrip sensor with polysilicon electrodes manufactured at CNM-IMB is introduced. The slightly resistive electrodes allows the determination of the particle's hit position along the microstrip direction using a charge-division-based readout. Preliminary results from laser, radioactive source and test beam characterization are given.

Speaker: Dr Ivan Vila Alvarez (IFCA - Instituto de Fisica de Cantabria-Consejo Sup. de Investig)

Slides 20101117_2DPolyStripsIvanVila.pdf 20101117_2DPolyStripsIvanVila.pptx

14:00 Characterization and Testbeam Analysis of irradiated Silicon n-in-p Pixel Detectors for the ATLAS Upgrade

Silicon n-in-p pixel detectors from the latest CiS production are detectors similar to ones from the latest ATLAS pixel production. First measurements of irradiated CiS n-in-p single chip assemblies (SCA) connected to the current ATLAS front end chip FE-I3 were performed during the last weeks. Characterization results will be presented from devices irradiated with protons and neutrons up to fluences of 10E15 n_eq, as well as results from test beam studies at the CERN H6B area. An outlook on the ongoing irradiation program and the upcoming analysis steps will summarize the talk.

Speaker: Christian Gallrapp (CERN)

Slides Characterization_and_Testbeam_Analysis_of_irradiated_Silicon_n-in-p_Pixel_Detectors_for_the_ATLAS_Upgrade.pdf

14:20 First measurements with planar pixel detectors after SLHC fluences

ATLAS SingleChip-Assemblies based on the FE-I3 readout chip have been irradiated with reactor neutrons in Ljubljana to fluences up to 2E16 neq/cm^2. First measurements obtained with a Sr-90 source in the lab will be presented. The collected charge will also be compared to preliminary testbeam results.

Speaker: Daniel Muenstermann (TU Dortmund)

Slides Muenstermann_RD50.pdf

14:40 The Timepix Telescope

A report on the development of a high resolution particle tracking telescope based on the Timepix pixel detector. Using the different modes of operation available in Timepix a Telescope system has been developed that can provide a spatial resolution of under 2 microns and a timing resolution to the order of a nanosecond. This track time tagging ability has been used to incorporate an LHCb/Beetle 40MHz readout to allow an LHC compatible device under test to be operated in an asynchronous beam. Initial results from testbeams with Timepix and other test targets from 2009 and 2010 will be reported.

Speaker: Richard Plackett (Glasgow University)

Slides Plackett_20101117_RD50_Telescope.pdf Plackett_20101117_RD50_Telescope.ppt

15:00 Discussion on Full Detector Systems

Speakers: Gianluigi Casse (Department of Physics), Gregor Kramberger (Jozef Stefan Institute)

15:30 Coffee Break

16:00 → 18:10 3D sensors

Convener: Richard Bates (Department of Physics and Astronomy)

16:00 Status of 3D detector productions at CNM

I will report on the fabrication of new 3D detectors devices for the Atlas 3D collaboration and other CERN experiments.

Speaker: Dr Giulio Pellegrini (Centro Nacional de Microelectronica CNM-IMB-CSIC)

Slides Rd50_3d.pdf Rd50_3d.ppt

16:20 3D Detector status at FBK

In this talk we present the latest results from the development of double sided,double type column 3D detectors with full passing columns at FBK. The main issues related to the fabrication process and preliminary results from the electrical characterization of several test devices will be discussed.

Speakers: Elisa Vianello (Fondazione Bruno Kessler), Gabriele Giacomini (Fondazione Bruno Kessler)

Slides Giacomini-RD50-web.pdf

16:40 3D-FBK pixel sensors: overview of recent results with proton and neutron irradiated sensors

3D Silicon sensors fabricated at FBK-irst with Double-side Double Type Column approch and columnar electrodes only partially etched through p-type subtrates have been irradiated and tested in laboratory and with 120 GeV pion beam at CERN SPS. We will present an overview of recent results from laboratory tests obtained with devices irradiated with protons and neutrons up to 5x1015 neq/cm2.

Speaker: Mr Andrea Micelli (Universita degli Studi di Udine)

Slides AM_RD50_17.11.10.pdf

17:00 Comparative Studies of Irradiated 3D Silicon Strip Detectors on p-type and n-type Substrate

Double-sided 3D silicon strip detectors, manufactured by CNM on p-type and n-type substrate, were measured after irradiation with sLHC strip- and pixel fluences. The device irradiations were performed at the proton cyclotron in Karlsruhe with 25 MeV protons. Results of measurements with a beta source and an infrared laser will be shown. After a radiation fluence of 2E16 n_eq/cm^2, the highest fluence studied, the detector on n-type substrate (p+ in n) yields a signal comparable to that of the detector processed on p-type substrate (n+ in p). A relative CCE of more than 50 % can be reached. The influence of different temperatures on signal, noise and charge multiplication will be discussed.

Speaker: Michael Koehler (Freiburg University)

Slides Koehler_RD50Nov2010.pdf

17:20 Test beam analysis on Timepix 3D pixel detector

An n-type double-sided 3D detector fabricated at CNM bump bonded to a Timepix chip has been tested in a pion and a micro-focused x-ray test beams. The resulst from both test beams will be shown. The x-ray test beam shows relative detection maps of the 3D pixel device. The pion test beam results show the absolute detection efficiency, cluster size and resolution for detectors with particles at a range of incident angles from normal to 18 degrees.

Speaker: Chris Parks (Glasgow University)

Slides 3D_testbeam_26102010_v2.pdf 3D_testbeam_26102010_v2.ppt

17:40 Discussion on 3D sensors

Speakers: Dr Chris Parkes (Glasgow), Richard Bates (Department of Physics and Astronomy)

19:30 → 23:30 Workshop Dinner

LA VILLA DU LAC, Divonne Les Bains

The menu: menu

The restaurant: Link to restaurant web site

Conveners: Maurice Glaser (CERN), Veronique Wedlake (CERN)